Buying a helmet, whether it’s for cycling, snowboarding, skating, wakeboarding, or any other activity, involves reading a lot of acronyms and technical terms. I’m here to tell you about some of the most common to make your helmet-buying experience a bit easier.
ABS (acrylonitrile butadiene styrene)
Acrylonitrile butadiene styrene is a type of plastic that you’ll often find in helmet shells. It’s a good choice for protective gear because it’s very strong and doesn’t weigh very much.
ABS is a thermoplastic, which means it turns into a liquid at very high temperatures—this makes it easy for helmet manufacturers to injection mold it into just about any shape, and you’ll often find it on shells without a lot of vents, like the Fox Flight Sport:
ANGi
The ANGi sensor is a small transmitter that lets your emergency contacts know when you’ve been in a bike crash. It’s made by Specialized, so Specialized helmets have a specific attachment point for ANGi sensors, but they work with most other helmets, too. You’ll need the Specialized Ride App to sync with the sensor for it to work.
When you take a hit, ANGi starts a countdown on the app. If you don’t tell the app that you’re okay, it’ll send an emergency notification when the timer is up. It sends a message to your emergency contacts with your last GPS coordinates and a message saying that you need help.
Helmets that have “ANGi” in the title, like the Specialized Ambush ANGi MIPS, have a sensor already integrated into the helmet, but you can also buy a sensor separately.
ASTM / CPSC / Snell
These are three organizations that certify helmets. If your helmet meets ASTM, CPSC, or Snell standards, you can trust it to save your life in a crash. At the time of this writing, these certifications are basically the same, so no standard is more reliable than another.
In the United States, all helmets are required to meet the CPSC standard before going to market, so you can trust just about anything you buy from a reputable retailer.
Dial Fit
A dial fit system is one that lets you turn a small dial on the back of a bike helmet to keep it snug to your head. It’s a crucial part of getting a good helmet fit.
BOA
Boa is a particular brand of dial fit system. It’s sturdy, durable, and reliable. You’ll also find Boa closure systems on snowboard boots, cycling shoes, and mountaineering gear.
Dual-Density Foam
Foam provides the life-saving shock absorption in a helmet (see EPS, below). Some manufacturers, like Kali Protectives, are now using two different types of foam in their helmets. In general, the dual-density foam provides two layers of protection; one that cushions mellower crashes and one that provides more protection in the case of a big hit.
Some dual-density helmets may also improve comfort by putting a softer foam next to your head. Other brands may use different types of foam for different purposes, so you’ll have to check the manufacturer’s specs to find out exactly what their dual-density system does.
EPS (expanded polystyrene)
Expanded polystyrene is what protects your head in a crash. It’s used in snowboard helmets, bike helmets, motorcycle helmets, car seats, and more. Note that it’s not the same as Styrofoam, but it’s very similar.
EPS is bonded to the outer shell of a helmet, which is often made of polycarbonate or ABS, and that’s what forms the most important part of the helmet. This is called the EPS “liner.”
Fidlock
Fidlock is a magnetic closure system that makes it easier to secure things to each other. You’ll often find it in winter helmets for skiing and snowboarding so it’s easier to clip the chinstrap without taking your gloves off. (If you’ve ever tried buckling a helmet with mittens on, you’ll know why that’s such a nice feature.)
Fit System
A fit system is what you’ll find on the inside of a bike helmet that keeps it snug on your head. They often have a Boa or other dial to tighten everything up. That dial pulls on cords that are attached to the fit system at different places in the helmet and pulls them closer to each other for a tighter fit.
Injection-Molded (in-molded)
In-molding is a process for creating and bonding the shell and EPS liner of a helmet. Basically, with an in-molded helmet, they’re both shaped at the same time. This results in a perfect fit between the shell and the liner, creating a very strong helmet. You’ll often find in-molded technology in high-end helmets with large vents.
If your helmet “dents” a bit when you put pressure on it with your thumb, it’s not injection-molded. Other methods can result in a pocket of air between the shell and the liner. This isn’t necessarily a bad thing, but in-molding is a better way to build a helmet.
Koroyd
Like EPS, Koroyd is a type of protective material that’s used in some helmets (pretty much everyone uses EPS, but Koroyd is used as an added protective layer). By using a series of “welded tubes,” Koroyd provides extra crumple protection to absorb impact forces, whether they’re direct or at an oblique angle.
You’ll recognize Koroyd by its distinctive bright green color, though it also appears in more muted tones, and you’ll find it in several different brands of bike, snow, and other kinds of helmets. In bike helmets, it provides added protection without sacrificing breathability.
You can see the black Koroyd tubes in this closeup of the Smith Forefront 2:
Wavecel
Bontrager’s Wavecel technology is very similar to Koroyd, but uses a slightly different shape. For the most part, though, they perform the same function and add protective features to a helmet without removing EPS foam.
MIPS (Multi-directional Impact Protection System)
MIPS is a branded term for a brain protection system that reduces rotational impact force. In short, it lets the helmet rotate around your head by 10–15 millimeters. This reduces rotational impacts and the chances that you’ll receive a concussion.
While it used to be very expensive, MIPS has come down in cost. So much so that you just shouldn’t buy a helmet without it (or another rotational protection system). Look for the little yellow dot on a helmet to show that it has MIPS built in.
You can see the dot clearly on this Smith Scout helmet:
POC SPIN (Shearing Pad INside)
POC helmets use a propriety in-house system called SPIN. This is equivalent to a MIPS system, but doesn’t require that POC license MIPS technology. It serves the same purpose, though.
Polycarbonate
Like ABS, polycarbonate is another type of thermoplastic that’s used for creating helmet shells. Compared to ABS, though, you’ll find that polycarbonate is thinner and lighter, so you’ll find it on higher-end helmets. It also has higher impact resistance than ABS.
All of that, of course, means that these helmets are a bit more expensive than their ABS counterparts. You can find both bike and snow helmets that use polycarbonate.
The Giro Grid MIPS ski/snowboard helmet, for example, uses polycarbonate to keep weight down:
Helmet Technology Over Time
Helmet technology advances all the time. These are currently the most popular terms and acronyms that you’ll see right now, but that could change quickly. If you have questions about other kinds of technology or you think we should add a particular term to the list, leave a comment below!
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