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Onyx M16 Inflatable Belt Pack – Test and Review

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Updated May 9th, 2024

Onyx M16 Inflatable belt pack review

If you are looking for a low profile SUP PFD to wear on hot days while paddle boarding, the Absolute Outdoor Onyx M16 is worth checking out. It is a USCG Type V inflatable belt back that is very low profile and worn around your waist. It gives you a Type III PFD when inflated if you need one. Keep reading to learn more about the Onyx M16 Inflatable Belt Pack.

Features of the Onyx M16 Inflatable Belt Pack

What we liked:

  • Small and lightweight PFD you wear in a small waist pack
  • Easy to re-pack and re-arm
  • Good PFD for calm warm water days

What we didn’t like:

  • It’s awkward to get the neck strap over your head after inflating
  • You need a new CO2 cartridge every time you inflate it

The Onyx M16 inflatable belt PFD is the most popular inflatable belt PFD available. It is a USCG Type V inflatable life vest. It has a couple thousand positive reviews on Amazon. It is worn like a small fanny pack around your waist. It has a D Ring attachment for attaching a whistle, light, knife, keys, or other accessories. It is very low profile and weighs about 1.5 lbs. It provides 17 lbs of buoyancy when inflated with a 16 gram CO2 cartridge. You can inflate using the mouth tube for additional buoyancy up to 26.5 lbs.

M16 and storage bag


The Onyx M-16 sells for between $62 and $90 depending on where you find it and what color you get. Several places sell it including Amazon and iRocker. There is also an upgraded version called the Onyx M-24 that has a big enough pouch to hold a water bottle.

USCG Type V PFD with Type III performance when worn

The Onyx M16 is a US Coast Guard approved Type V inflatable PFD or Personal Flotation Device. It counts as a USCG Type 3 PFD when worn by adults. The Type V classification means it’s an inflatable life jacket. It is a manual inflating device. This means it doesn’t inflate until you pull the cord. It will not automatically inflate when you hit the water.

If you are somewhere where you are legally required to carry a type III PFD on your paddleboard you can use the M-16 Belt pack. For it to count though it has to be worn. You can toss a regular type 3 life jacket in the storage bungees on your board and be legal without wearing it. You have to wear a PFD Belt Pack for it to count.

See our article on paddleboards and PFD requirements to learn more about when PFDs have to be worn.

inflated cushion


Onyx specifies that the M16 will fit a size 30 52 chest. It is worn around your waist so in reality, it will fit a size 30″ to 52″ waist which covers almost any adult. A very large person may have a challenge getting the neck loop around their neck after inflating it.

How does it work?

You wear the M16 Belt pack around your waist. It’s fairly small and not too noticeable. It’s a lot more comfortable to wear than a regular Type III life jacket.

When you need a life jacket, you have to pull the cord. This will inflate the PFD. At this point, you’ll have a big square cushion of air attached to your waist.

There is a neckstrap on the top of the air cushion. You need to pull this over your head to wear the cushion as a PFD. I think a bigger, larger person will find it challenging to get it over their head.

M16 packed not inflated
M16 inflated cushion
M16 inflated around neck

We took an Onyx M16 out to the lake and inflated it with the CO2 cartridge.

The hardest part about using the M16 is finding the pull handle in the water. Our water is murky so you can’t look down and see it. It took me a bit of feeling around to find the handle to be able to pull it. Once I found it, the effort to trigger it is fairly low.

After inflating it leaves you floating in a seated position. It’s not too difficult to pull the neck strap over your head. You will need to remove any hat you have on to do it. There isn’t enough extra strap to go over anything but your head.

After that, you can comfortably float around with it. It’s not going to turn you face up if you are face down in the water. If you aren’t conscious you won’t be able to pull the cord to inflate it either.

When to use a PFD Belt Pack?

PFD belt packs are PFDs you can wear when you don’t need a PFD. If you are in flat waters near shore on a calm hot day they are a good option. This assumes you can swim and are comfortable swimming in the water where you are. If you are more concerned with being comfortable and want to wear something just in case then it’s a good option. If you are doing paddle board yoga and want to wear a PFD in case you fall in the water and are separated from your board, this is a really good option.

When not to use a PFD Belt Pack?

You shouldn’t use a PFD belt pack anywhere you think you actually need a PFD. If think you are going to end up in the water a lot and need help floating, don’t wear one. Get a regular PFD. If you aren’t a good swimmer, don’t wear one. You will have a hard time using it in the water. If the water is rough with a lot of waves this isn’t the PFD to wear either. In most cases, a traditional life jacket is a better option.

Rearming and repacking

Packing and rearming the M16 is easy. You deflate the air cushion by pushing in on the end of the mouth inflation tube. You can use the black plastic cap or just push into the end of the breath tube with your finger. Squeeze all the air out by smushing and rolling the cushion while pushing the valve open. You need to fold it 3 times to get it back in the size and shape that fits into the waist bag. The air cushion is clearly marked where it needs to be folded with labeling for the folds and order.

It took me about 5 minutes to get it packed back into the bag after deflating it. Screw in a new 16 gram CO2 cartridge and velcro the bag shut.

Inflator cartridge

Where to get CO2 cartridges for rearming.

You can get the CO2 cylinder anywhere that sells 16 gram CO2 cylinders or buy m 16 rearming kit. The rearming kit is just a generic 16 gram CO2 cartridge in Onyx packaging.

Onyx Unisex Belt Pack Manual Inflatable Life Jacket (PFD)
Onyx M16 product image

The Verdict

The Onyx M 16 Inflatable Belt Pack is a good stand up paddle boarding PFD to use in the right conditions. It’s great for hot calm days where you don’t want or need to wear a PFD but the laws say you have to. It must be worn to count as a USCG Type III PFD so you can’t just strap it to your board and go. It’s best to think of it as an inflatable air cushion you’ll have with you if you need one if things go wrong.

Doug Ryan Portrait Skiing 200x200

Ryan Craig
Co-Founder & Chief Editor

I am a total gear nerd and love learning how things work and thinking about how they could be improved. Nothing excites me more than trying out new gear. I’d rather spend 3 hours taking my bike apart and learning how to change something than go to a bike shop. These days, I reside in Michigan by the Great Lakes and go skiing, biking, and boating as much as possible. Visit our About Us page and learn more.


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