Me seeing this in 2018: “Lame” Me seeing this during Coronavirus: *watches intently*

@Zachomara

4 жыл бұрын

His activated charcoal needs to be crushed into a powder first. The other thing he needs to do is to alternate the materials 3-5 times in order to filter out biological agents and other smaller compounds like the newer chemical agents. While not fool proof (only a closed system is completely fool proof, and even then its iffy) it could help increase the protective agency of the mask.

@sentaukrai

4 жыл бұрын

IMPORTANT!!! WATERTIGHT IS NOT THE SAME AS AIRTIGHT!!! Air molecules are smaller then water molecules and there a mask can be watertight but not airtight. Air tight IS water tight Watertight IS NOT airtight

@AntiSoulcial

4 жыл бұрын

SCORPION FIRE You can’t buy them on Amazon anymore.

@HieuNguyen-jg4dc

4 жыл бұрын

letting you know those filters are not good against coronavirus

@MrDisaster88

4 жыл бұрын

You want P3 filters for corona-protection, P3R D preferably. And yes, they are still available in some places. Ordered and received a box of dirin 230 p3r d filters from germany last week, at a reasonable price too.

This is the first homemade gas mask I've seen which has an interchangeable filter, which is good. So yay.

@MechNinji

6 жыл бұрын

haha! I'm glad you like it! :D

@nine552

4 жыл бұрын

SaavageTurtle 41 it looks cool but it will kill you if you use it

@big_bob_s3747

4 жыл бұрын

its good if you like dying

@saavageturtle4121

4 жыл бұрын

@@nine552 well, I'm still alive

@darc4165

4 жыл бұрын

@@MechNinji that air buble out part of mask perfectly fits for a gas mask but i have a another idea that part for fits too for carbon dioxide out part u put filter to under water air part and out carbon dioxide to out air part is a better idea i think btw sorry for bad english

That soft "white rubber" disc you removed to make the attachment point for the filter should have been kept as an exhilation valve, otherwise you are breathing both in *AND* out through the filter material. I would suggest using a 60mm mask to 40mm filter adapter, glued into a new hole either above or to one side of the exhilation valve and using that to attach a filter.

@markpolzer6746

Жыл бұрын

That is so right, first thing I thought is why is he destroying the exhaust valve.

@sbrim30

Жыл бұрын

So you need a 60mm for a 40mm?

@dj1NM3

Жыл бұрын

@@sbrim30 No, just so there is something with a NATO 40mm thread to glue onto a new hole, so that standard filters can be used. 60 to 40 adapters are just a conveninet piece of hardware to do that with.

@sbrim30

Жыл бұрын

@@dj1NM3 thank you

@setoinenrikkihappo5823

11 ай бұрын

You took the words from my mouth... or rather my fingers

For all the commenters who say “you can get a military grade gas mask for under that” yes, that is true. BUT, this video was probably for the fun of making it yourself and testing it out.

@deckmastercelticguardian8582

4 жыл бұрын

Yes but the title of the video does not say so.

@AngelicaMartinez-pv7ui

4 жыл бұрын

sun-dye

@myafield4039

4 жыл бұрын

I cant find a military grade for cheap anywhere

@bamsroom1782

4 жыл бұрын

And to keep you off radar or if they are sold out

@petrolak

4 жыл бұрын

This really dumb way to do this though . You could make a simple silicon rubber plug for the snorkel, drill hole for the filter on the side instead of front and keep the outlet valve. It would be easier to breath in and out and you could still use it for snorkeling, just plug the air intake hole with a screw cap. Or just fill the snorkel with charcoal and be done with it.

It's only airtight on people WITHOUT facial hair under the seal.

@joshpup1580

4 жыл бұрын

why

@namelessman8097

4 жыл бұрын

I've heard you can cover your beard in vaseline and still get an airtight seal.

@2-_-V-_-.2

4 жыл бұрын

@@joshpup1580 because the hair make small gaps between the mask and your face Sounds logical right?

@Oneiromancy

4 жыл бұрын

@@professionalschizo What masks does your army have?

@totallyfrozen

4 жыл бұрын

Robert Mackrell If you’re in the Army, then you know about your M40-A1 promask. So why are you comparing this homemade snorkel mask to a $400 military grade mask?

Gonna wear this into gym, people deodorant bombing

@MechNinji

5 жыл бұрын

hahaha! #LifeHack

@cfat3379

4 жыл бұрын

prb need an abek rated filter to actually survive in there

Very creàtive build, I would recommend layering the filtering system as a t-shirt layer on the 1st layer of the filter, a sponge as the 2nd layer, 1/2 activated charcoal, card board layer covered in holes, 1/2 layer charcoal, another card board layer covered in holes then cotton balls. When testing any home made gas mask use a road flare burning in a pot. If you can't smell it or choke while breathing in ur gas mask works. Sgt. Anthony Har

@xarv368

Жыл бұрын

Creative? Rather it is to complicate life. With that money I would buy a gp5, a Soviet clone of the m9 mask, a Yugoslav mask. Waste of time for a dysfunctional artifact.

Under 30 bucks you can also buy a Russian GP- 5, that will be reliable, (ten bucks) and a Polish FP-5 filter (10- 15 bucks) and you have a gasmask that *will* actually be reliable and *will* save your life! *DO NOT USE THE FILTERS THE GP- 5 COMES WITH! THEY CONTAIN AZBESTOS!* But this is quite cool for a scavenger cosplay.. If you are going to make this, crush the activated charcoal, it will be more effective :)

@unknownunknown2433

4 жыл бұрын

Sense I’m stuck in China this will be real helpful

@JeanAlesiagain3

4 жыл бұрын

what gas mask should I purchase if I don't mind the cost?

@user-db8lj6wt7z

4 жыл бұрын

JeanAlesiagain3 Get a Isreali M15

@junglejim9551

4 жыл бұрын

@@JeanAlesiagain3 Avon S10/FM12 (pretty much the same mask, FM12 is just an updated and better S10

@Piter1111111111

4 жыл бұрын

@@JeanAlesiagain3 CM-6M Gas Mask

I live in Philadelphia PA, riots and gas are a major concern right now. Thank you for showing me how I can attempt to keep my family safe without spending almost $1000

That one way valve you literally cut out of the mask.. would have actually been incredibly helpful to the mask. As the valve allows air out of the mask, without allowing air back in and ruining the seal of the mask.

@studmcmuffin8844

3 жыл бұрын

It's one way for water but not necessarily for gas I'd imagine

@Ocean_Man_

2 жыл бұрын

yeah it would have been better if he were to screw on that air filter thing on top of the mask, although that wouldn't be so unconvinient to use

i'm so happy i found this video, i have been having a hard time with my allergies. now i can go out side more often

with an exhale valve and a little more care on the filter , ie make a better particle filter and crush and pack the charcoal this could be a serviceable mask , heck you could even add a drinking tube ! good stuff

am i missing something here???? u cut off the inhale hole at the top and blocked it off. then changed the original exhale hole on the front to an inhale hole with the filter... now u have no exhale hole.... so the mask dosnt work at all.......

@auxometer

3 жыл бұрын

It does work however you risk inhaling too much CO2 because there's no way for "used up" air to escape the mask other than the filter. So that CO2 will stay in the filter after you exhale and then be inhaled again, and again, and again, which can kill you. Some older masks didn't have exhale valves because they were usually civilian and used for evacuation so not for a long period of time.

Me seeing this in 2018: no thanks ||||| me seeing this in June 2020: can’t wait to stop choking on tear gas ✨💗⚡️🧚🏼

@throwanitback

4 жыл бұрын

this is a joke I fully understand it’s not a CBRN filter

@ChaoticVampire

4 жыл бұрын

@RandomHoboLivingintheForest *you should protect yourself while protesting. fixed it for ya.

@throwanitback

4 жыл бұрын

Isomatte I didn’t riot and still got tear gassed you raging buffoon

Also, with the filter, you probably smelt a little spray because the activated charcoal/carbon wasn't fine enough, the pelts are big and leave a lot of space, you can buy finer activated charcoal in the pet store, that would be better for a mask, or if they don't have it you can just grind the big pellets a little to make the filter work a bit better, just some friendly advice, anyway great video and great mask too.

@MechNinji

6 жыл бұрын

Yes, the sounds like it would help quite a lot! Good idea! That is definitely something I'm going to have to try! :D

@vodka5410

Жыл бұрын

could you use charcoal powder?

i get the full face mask scuba and i get the half mask respirator and put the half gas mask in to the scuba mask does that work? sorry bad english

Just one question, how is air supposed to get out? If you want it to go back trough the filter there would be co2 buildup Also you could buy a lot of surplus gas masks,adaptors (for gost or 60mm gas masks) and a m80 israeli filter (even in date le you search hard enough) for the same price

please show us how to bolt the cup to the mask. bolts look very long. What do they screw into?

Good tip!! Make the first layer instead of cotton use your mouth mask preferebly your ffp2 or ffp3 class mouth masks ( the ones the hospital uses)

Keep the exhalation valve and add a separate hole for the filter canister.

@Polarcupcheck

4 жыл бұрын

I know, this guy knows nothing about respirators. To destroy a perfectly good exhale valve.

@Polarcupcheck

4 жыл бұрын

@Sean Sigmund Its foolish. If you want to breath out easier and not have the mask fog up, you don't destroy an industrial made exhale valve. Its a waster of good craftsmanship.

@Polarcupcheck

4 жыл бұрын

@Sean Sigmund You need to learn about respirators. That needs to happen first before you comment.

@HazmatUnit

4 жыл бұрын

@Sean Sigmund makes it worse because you won't about carbon dioxide

@shwaffy2120

4 жыл бұрын

hazmat unit there’s no intake valve so it comes through the filter and goes out through the filter and it has a nosecup to stop it from fogging up

This is awesome and actually really useful

How hard was it to breathe with the mask on?

how well would it work against tear gas?

thank u for sharing the idea..luv this..just like that..yeah

I've a school prjct which is i need to make something that can reduce air polution . Do y think i can make ths ? Ahahahaha im just afraid ppl can't breathe once they using ths . Please give me some opinion ?

How long can you wear this before you are blinded by the fogging on the lens created by the moisture from your breath?

So if you had the means a 40 mm nato adapter could work if you found a way to set it up.

I'm watching this video because both of my older brothers did a "gas attack" on me and my little brother.

@Biden_is_demented

4 жыл бұрын

Your brothers like to fart in your general direction, eh?

Corona virus is spreading and this vid is now in my recommendations 😂😂

@anveemomin999

4 жыл бұрын

Let justice prevail

@militaryequipmentreviews5650

4 жыл бұрын

Came here to make one but i decided to buy a gas mask for 50 dollars cause its so hard

@yipfred1751

4 жыл бұрын

problem is those cotton ball-made filter does not meet the safety standard as P100 filter.... you need filter that can block those particulate that carry the COVID19... u dont need active charcoal, those are for absorb harmful gas...

@matolittleelkwells5377

4 жыл бұрын

@@yipfred1751 use a merv 16 hvac filter they filter to 0.3 microns at 95% efficiency they aren't cheap though but last for a year and you could get multiple filters from one unit cost around $95 at Walmart

@big_bob_s3747

4 жыл бұрын

@@matolittleelkwells5377 or get a filter that does more (which you can) for the same price or less

in a real tim scenario, that little something you smelled, just killed you. Nice Toy ! well explained.

Why would you wanna do this when you could by an actual gas mask for less than 20 bucks?

@MechNinji

6 жыл бұрын

Because you cant buy an "actual" gas mask for less than $20. At least not one anywhere close to the same quality. You could buy a few paper dust masks though, if that's what you mean.

@_iso_553

6 жыл бұрын

Mechanical Ninjineer yes you can. rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F263415407418 it has an asbestos filter but for an extra 15 bucks you can get a NBC filter without asbestos and those filters last hours. You could use the asbestos one too in an emergency

@MechNinji

6 жыл бұрын

That's a GP-5. There has been some debate about weather or not the filters are safe for use.

@_iso_553

6 жыл бұрын

Mechanical Ninjineer we know for a fact it has asbestos but if the filter isn't damaged it will work and probably not leak and even if it does short term asbestos exposure is way less serious than most gasses that you would need a mask for.

@jaleeckflathead9640

6 жыл бұрын

I have the gd5 but this have a bigger lense to look out from. With the gd5 we could use the Poland filter. It's like $15 on eBay. But I'm going to make your diy gas mask. Much more view to see.

Great video! Just a question, is there an exhale valve so you can’t suffocate?

In the filter deploy Active carbon?

is the lense made from a type of silicone? some gasses can eat through silicone

@Zachomara

4 жыл бұрын

Emergency only. I'd say CS (military style tear gas), and some larger nerve agents are what its designed to protect against. It's not for long term use, so it should be used exclusively to GTFO of the area.

What if we have no snorkling mask....can you sir make a video of diy and around the house things like plastic bottles....we really need your help....FROM PHILIPPINES

You should have added a 60mm to 40mm nato adapter to screw on some military filters

wouldn't it be easier to make the snorkel attachment into the filter and leave everything else intact ?

wouldnt it be easier to just use the air intake tube and mount the filter onto it? that way you could keep the exhale vale in the front of the mask

I’m thinking about filling the mask’s tube with granules of activated charcoal(used in aquarium filters) and some wadding and making 2 holes on the walls in the internal bottom of the tube to join all the 3 sections of the tube and use them as “air in”, and to effectively make the tube an actual reusable antigas filter. And maybe also use part of a vacuum cleaner’s sack (which usually block particles as little as 30 micron) to seal the top. Would it be good?

@emantide6306

4 жыл бұрын

If you want to block coronavirus use a HEPA vacumn filter .Has to be smaller than 1 micron

Thanks..i'm going to try and incorporate a hepa filter in there somehow

Ok but will this help me not breath in the tear gas at protests

Elementary question....How does the expelled air (from your lungs) get out of the mask? Thanks

@not.spir0s

2 жыл бұрын

this guy didn't make one, but i was thinking that the top part from the scuba mask that he took off and sealed up may be made to be a one way valve so that you could exhale through it

IT'S FANTASTIC! THIS IS A PIECE OF HOT GLUE WITH A LITTLE MASK ON IT!!!

That’s so cool!

Does This Filter Tear Gas?

Isn't the MIRA Gas Mask nearly the same in shape with that Snorkel?

Great Show 🤝😎👍

You can use the filters used for home ac filter

that air buble out part of mask perfectly fits for a gas mask but i have a another idea that part for fits too for carbon dioxide out part u put filter to under water air part and out carbon dioxide to out air part is a better idea i think btw sorry for bad english

I would like to make one, probably already made, complaint in that you shouldn't have painted the mount before gluing it in place, as that creates a point where it can fail very easily

That's really awsome

One criticism on your mask is mounting the filter directly on the mask. I'm ex military an this type of mask gets real uncomfortable when you have to wear it for an extended time. A much better option would be using a 40mm tube to connect the mask to the filter, ie like the ww1 type masks. It not only takes the weight off your head and neck but let's you use a much larger filter than you could mount to the mash itself. I would not close off the top port either but instead convert it to N exhaust only port like military masks have. I doubt you could even get a civilian version mask for the same cost as what it would cost to make one. That I would have to see proven. Plus military masks have much more restrictive vision than does the mask you demonstrated. Using plastic weld instead of glue is also a better option. It bonds the two pieces into a single part. Hell they use it to build aquariums that hold back hundreds of pounds, using it to make a filter housing would be easy, although it does take 72 hours to fully cure. Additionally I don't think any of us plan to go to war in this mask so it does seam a reasonable use for chemical fumes and dust. Besides it looks like a blast to build anyway. Lol

Smells like awesome!

@MechNinji

6 жыл бұрын

hahaha! Thanks!

this is great, perfect for protesting in Thailand

can this prevents smoke entering your body?

@haywoodyoudome

Жыл бұрын

Only if you put a large plug in your asshole.

Very cool idea I might try this. There is a couple of problems though. First, that rubber valve you removed from the mask is the exhale valve. You need that in order to efficiently breath out of the the mask. If you remove it, you'll end up having co2 build in the mask because your breath has to work its way back through the filter medium. Second, cotton is a poor choice for the main particulate layers. You need to use some sort of hepa filter (I recommend cutting part of a furnace filter). Make sure the MERV rating is at least 1900. This is because some cheaper filters will be made of fiberglass and breathing in fiberglass particles is a no no.

@Blyegh

4 жыл бұрын

ORANG BOI I thought HEPA wasn’t affective for protective masks? Isn’t that why mask manufacturers use ULPA filters? Because U15 ULPA is capable of filtering 99.997

@patc5919

4 жыл бұрын

@@Blyegh Interesting, I looked at the packaging for those furnace filters and the higher tier ones say they can filter viruses and bacteria. It could be that they don't filter as good as other materials though.

@Blyegh

4 жыл бұрын

ORANG BOI From what I’ve heard, while it’s effective for filtering out particles it’s only good to an extent. In a situation where we don’t have proper protective masks and only have limited resources to use, I guess it’s better than nothing at this point. But I wouldn’t heavily rely on a HEPA filter because it doesn’t filter out all of the smaller particles. U15 - U17 ULPA filters are capable of filtering out 99.997+, because ULPA filters are specifically designed to filter out nearly 100% particles that are 0.3 microns. I’d be interested in seeing anything else that could prove me wrong. I could definitely use that sort of information right about now hahaha

@the_goat_himself2541

2 жыл бұрын

Do you have any suggestions to make the exhale chamber, i orderd the same mask as him as a fun little learning project… but I’ve gotten pretty seirous with it considering that it can save a life… I was thinking put the filter at the top of the mask wear air originals comes through, any thoughts on how I can do it?

@dj1NM3

Жыл бұрын

@@the_goat_himself2541 The mask in the video already had an exhale valve, that's the hole that @MechNinji butchered to put his filter mount on. A better solution might be drill a hole in the clear plastic to one side of the mouth/nose cup and mount a filter there instead, that way breathing out goes straight through the valve and breathing in comes through the filter.

5:33 looks like DEET bug repellent.... thats the good stuff. lol I got my finnish gas mask... I think they are still fairly cheap too. but I might would have flipped the "exhale" valve so you only get intake through the filter... then some sort of cobbled together valve for exhale gasses.

im happy you made this, i have full blown gas mask like this now, and i can scare the hell out of my brother. e p i c

Great job

Great share thanks!!!

I made a filter with a tuna can for my own mask lol I am gonna see this one video is good so far

thanks bro cause millitary gaz mask are prohibited here in france

This is good but the filter can expire within a day of wearing it so seal the filters to keep the charcoal/carbon from expireing

where's the exhaust valve?

Double breathing the filter. No-no. Should leave the exhaust valve intact and cut a new port for the filter.

AS a former service man who worked with NBC and similar in employment, great but, the one way valve should have been left and just tap a 40mm for your filters in case you run across reg. filters, place a secondary filter cover over said one way valve, after you spend hours in it or it fills with condensation sweat or clouds up in firefight, learn to make better than those $200+ models, and learn how to use these... technologies

Ways to make this better: keep the exhale valve and add the filter above it or beside it or use a hose, make a rubber disk and make an intake valve to double the filter lifetime, this will cost more but it will work way better. I can also explain why he smelled the aerosols faintly: he used cotten pads but you can buy 3m particulate filter of amazon pretty cheap they are in the shape of standard 3m respirator filters but cotten packed pads that can be cut to fit, cheap and effective but i would reccomend getting a cheap gas mask if your dealing with tear gas or anything or in a country with chemical warfare threats

Him: I'll leave the links to the materials in the description The Description:

love your vid but i didnt use the can i used the 2 side half gas mask refillable filter only 6$ and glued the half gas mask into the full face mask snorkeling

@MechNinji

6 жыл бұрын

cool beanz! :D

I love how you can buy a real gas mask that will actually protect you against stuff for the same price

@Blender.bunker

Жыл бұрын

Eh but it’s funnier to build it

My suggestion is that the activated charcoal sould have been crushed lightly, because the center of the pellet is useless oherwise and is wasted overall great video

Wouldn't it have been simpler to use a flex tube to connect a filter to the original snorkel opening?

@Zachomara

4 жыл бұрын

It probably would be, but you may not get enough air once the filters are in place.

@Blyegh

4 жыл бұрын

David Kermes He has to make the mask more fashionable. I saw a similar video where a prepper used that same snorkel device, but he instead used the snorkel valve. It looked really weird... and honestly it probably would not have been that much more effective than this design.

Extreme awesome

If you cant find an o ring that you need, some gasket maker at autozone or oriely's should suffice. Aisle 6 at autozone

who is here after hearing about the Corona Virus?

@yg6484

4 жыл бұрын

Blendi Klimenta me

@profantigona6059

4 жыл бұрын

Me

@unknownunknown2433

4 жыл бұрын

I’M LITERALLY STUCK IN CHINA

@blendiklimenta6657

4 жыл бұрын

Unknown Unknown Damn, be safe bro. Hope you make it back🙏🏼

@reiner5593

4 жыл бұрын

@@blendiklimenta6657 I'm Trying to make mine now that Egypy is the First Contury In Africa to have the Coronavirus. Nah shit

is it better than n95. XD

Wrong connector for shtf, you should put a pet bottle cap on the intake and use 600ml pet bottles, they are very easy to manufacture and have a lot more air travel and surface area in the lightest package possible.

amazing

Not sure how the exhale would be without a valve system. Gas masks inhale through a filter and then exhale through a valve.

Question: rather than completely remove the snorkel, why not shorten it down to a small stub and mount the filter directly to it? That way the air outlet diaphragm is still there, and I bet there's a way to actually attach a standard NATO 40mm filter up there, with a bit of ingenuity. Anyone see a mechanical reason why that wouldn't work?

Can we use regular charcoal crushed into a fine powder?

@francescoparavidino

5 жыл бұрын

It wolud not be as effective Around 100 Times less

@apiix9519

4 жыл бұрын

Not a powder though

1:48 you shouldnt have done that. just reverse the valve to make it an intake valve. and then make the intake at the top your exhale valve. also to increase efficiency, crush the grains of charcoal. and your particle layers should be a bit thicker and/or made from M3's particle filters. you can get packs of them from walmart

This is really useful during the coronavirus outbreak

@big_bob_s3747

4 жыл бұрын

No it's not, do not trust your life on that, he made it for a fun video, use a half-face 3m respirator or buy a gas mask (make sure its the right size for you). If you get an old Russian gas mask (gp-5, gp-7) buy a new filter for them like a polish FP-5 filter. If you want more info for gas masks go visit the channel Weaponsandstuff93. Have a good day, stay safe :D

@sphinx2077

4 жыл бұрын

@@big_bob_s3747 I know, there's no way I'd wear something home made 😂

@big_bob_s3747

4 жыл бұрын

@@sphinx2077 ok good😂I was just making sure. stay safe out there

@gunplaytv

4 жыл бұрын

@@sphinx2077 unfortunately alot of people will have to.

Nice gas mask. ☺️👍

@MechNinji

5 жыл бұрын

Thank you!

Lol I wanna see you test it against tear gas.

If you keep the outlet valve, it will me much easier to breath.

this will help my anti-riot gear gear

I heard that if you fill the inside with carbon monoxide first it helps you breathe better

@kryptic1995

6 жыл бұрын

lmfao

@LockheedC-130HerculesOfficial

5 жыл бұрын

I tried it and it works! -i have lung cancer tho-

@timothystrickland5347

5 жыл бұрын

Tested. Approved. 😵

Din't need to destroy the facepiece or go to all that trouble. Just plug the exhalation channels at the top, and modify the air tube to take the filter.

*Laughs in medium sized 3M 6800 full facepiece panoramic gas mask respirator equipped with 7093 encapsulated P100 advanced particulate filters*

Genius. Can you beat that Micgyver?

Really cool, one of the most unique homemade ones I saw. (Edit, just realized I already commented on this video, lol)

@MechNinji

6 жыл бұрын

haha! Well thanks! I'm glad you liked it! :D

Is this one safe, dosent contain chemicals??

@joshpup1580

4 жыл бұрын

it would why dong ding ding don't hey

@clorox821

4 жыл бұрын

I mean the filter its self is safe its only activated charcoal doctors make people eat it in a OD situation.

how to do upgrade to stop infection by CoVid19 Corona Virus?

@oaf1575

4 жыл бұрын

dont build this, its useless for that

@clorox821

4 жыл бұрын

Just get a 3m p100 filter with a 3m half face respirator

You could just buy a gp-5 whit a new filter but its more fun wen you build a DIY gas mask

if something is water tight doesn't mean air tight water molecules are bigger and oxygen can get through some spaces water cant there are actually aerogel masks that use this technique to breath underwater its still being tested tho

I bought Drager mask + EBAK filter in 20 bucks (with VAT) past week. But nice try.

Thx now I can make a gas mask

I think the.. the... green Alien ate him for helping humanity....

You need an intake check valve and exhaust check valve