Zephyr Updates
NRS has released an updated version of this belt-style PFD. The new model no longer sports the clear window at the front of the pack, and it features a 24g CO2 cartridge instead of the 16g cartridge included with the model we tested. There are some added D-ring attachment points, as well. Compare the two below; the older model is shown first, followed by the updated version.
We are linking to the updated model and plan on testing it soon. Until then, this review still references the previous iteration of the Zephyr.
Hands-On Review of the Zephyr
The NRS Zephyr is a manually deployed, unisex inflatable belt PFD that comes in just one "universal" size. A type V PFD with a type III performance, it's made of polyester with a high-efficiency welded bladder and operates with a 16g CO2 canister.

Quick inflation and an adjustable neck strap are two of the things we like about this model.
Photo: Jenna Ammerman
Comfort
Compared to the other belt packs we tested, the Zephyr has a strap of medium width and medium softness, which we think is pretty comfortable to wear over clothes or against the skin. Behind the actual inflatable pack is a soft fabric pad that keeps the scratchier fabric and velcro from touching your skin. We're impressed that the velcro — which lines the bottom and both sides of the inflatable section — doesn't seem to catch or rub while wearing. This is not the case of all the other models we tested. A simple buckle around the waist makes it easy to adjust the Zephyr, and a little loop holds the remainder of the strap tail out of the way. Though it's not the lowest profile inflatable PFD that we tested, we still think it's comfortable to wear, and we frequently forgot it was on while paddleboarding.
That being said, none of this kind of PFD is ideal for sitting. For it to function properly, you have to wear the bulky inflatable section on the front, which gets in the way of comfortably sitting down. All inflatable belts are pretty uncomfortable when worn in a seated position. They're all much better for a standing activity like SUPing or sailing. The size of the "fanny" portion of this "fanny pack" also creates a fairly stiff section that's a bit annoying to wrap around your waist. Fortunately, the forgiving padded section behind the pack helps to alleviate some of the discomforts you might otherwise feel.

This back panel is surprisingly comfortable to wear.
Photo: Maggie Brandenburg
Mobility
For something that only wraps around your waist and doesn't even come close to your shoulders, any PFD of this style is going to offer some pretty top-notch mobility. The Zephyr helps keep your legs mobile by having the pull tab for deployment located slightly off-center, so it doesn't catch between your legs. However, what makes this model a good choice for mobility is how well the inflating function works.
Wearing a PFD this low profile and specifically made only for expert swimmers, you don't expect to deploy it every time you get on the water. But you want to know it will work if and when the day comes that you need to use it's inflation properties. During our testing, the Zephyr consistently proved itself to be reliable on deployment and easy to use as an inflated flotation device. It explodes into a square-shaped yellow pillow and has an adjustable neck strap that's long enough to easily fit over your head and pull to the tightness you need, based on your height. This may sound elementary for this type of PFD, but the other belts we tested proved to be more difficult to use when inflated. Since the situation in which you may deploy an inflatable PFD will probably involve a fair amount of panic, we think it's important to have one that's easy to use. The Zephyr is also the simplest and easiest option to deflate, pack up, and rearm.

An adjustable neck strap helps make this easy to use in the water.
Photo: Maggie Brandenburg
As is true of every inflatable option in this review, it's difficult to swim with the inflated Zephyr resting on your belly and looped around your neck. You can float (obviously) and maybe get a halfway decent backstroke going, but you're not going to go far once this is blown up. As a ready-for-action fanny pack, it's also not ideal for swimming when packed up, as it creates a fair amount of drag.
Versatility
The first thing to note about any inflatable belt PFD like the Zephyr is that it's only intended for expert swimmers, and to be legal, it must be worn on the front. This definition of who can safely wear this type of PFD is limiting. It's mostly intended for paddling, though the fanny pack design might not be everyone's favorite for sit-down paddling. On a SUP, though, it's pretty awesome. Also, if you choose to wear it a little higher on your waist, you can easily rock this thing for canoeing, kayaking, sailing, or even on the pontoon or yacht.
Rearming the Zephyr is a simple process. NRS recommends purchasing the full rearming kit that includes the 16g CO2 canister, as well as a little green tab to indicate that the system is ready for use. This small plastic tab disappears when you pull the arm that deploys the airbag — that means that it joins the aquatic ecosystem as yet another small piece of trash. Though NRS doesn't mention it in their directions, you can rearm the whole thing the same way but without using the little green plastic trash piece. It won't have a nice green "I'm ready" spot in the indicator window, but it also won't fling garbage away into the sea. And, like all the inflatable PFDs we tested, there's an emergency mouth-inflate tube if you have forgotten to rearm your unit.

This inflatable is one of the simplest and easiest to rearm for next time and pack away.
Photo: Jenna Ammerman
Durability
The strap and case on the Zephyr are made of (non-ripstop) polyester, and the bladder is welded. True to what we've come to expect from an NRS product, the quality of construction is solid, and we had no issues using this PFD. Even scouring other internet reviews didn't dig up any dirt on potential failures of the Zephyr. NRS also backs it up with a lifetime manufacturer's warranty.
The only mildly annoying thing we noticed is that the bladder and pack are supposed to be completely dry before repacking them, which just takes time. We assume this is to prevent potential yuckies picked up in wild waters from growing inside your PFD, so this seems like a reasonable step to take toward extending the life of your inflatable. And, obviously, poking a hole in the bladder renders it useless, a problem foam life vests do not face.

Solid materials, solid construction, and a comfortable design.
Photo: Maggie Brandenburg
Value
The Zephyr isn't the cheapest inflatable we tested but it also isn't the most expensive. We like its compromise between comfort, usability, and reliability. For the mobility and peace of mind that it brings to the table, we think it's worth a few extra bucks.
Conclusion
The NRS Zephyr is a comfortable belt when it's packed up, easy to use when deployed, and simple to rearm and repack, making it our Top Pick for an Inflatable Belt. Despite not being the smallest or cheapest inflatable we tested, the Zephyr brings a great blend of comfort with the reliability of knowing it will perform admirably when you actually need it.

Paddle comfortably with the reliable Zephyr.
Photo: Jenna Ammerman