Are you looking to get yourself a new mask for snorkeling, SCUBA diving, or freediving? If you’re not a veteran of these sports, finding equipment that is both high quality and personally suitable for you can feel like an overwhelming task. There are so many different masks to choose from! However, there are a few critical features you should always look for in a dive mask to ensure it meets basic safety and performance standards. It doesn’t matter if you’re new to diving, or just a casual snorkeler, these features are important for everyone to consider!
Here’s what to look for in a dive mask if you want to be sure you’re getting something safe and dependable for your next underwater adventure:
- Tempered glass lenses or faceplate
- High-quality silicone skirt
- Sturdy, easy-to-use strap buckles
- A robust frame (unless the mask is frameless)
- Optical-grade glass (optional but recommended)
- BONUS: The most important feature of any dive mask
Other features that you should consider for your personal needs include: mask volume, the number of windows, prescription options, skirt opacity, and purge valves.
Let’s go over each one of these features in more detail!
1. Tempered Glass
What is tempered glass?
Similar to the concept of tempering steel, tempering glass involves special chemical and thermal treatments that make it stronger relative to untreated glass. Specifically, tempering creates high compressive stress on the outer surfaces of the glass (at least 10000 psi) that is balanced by high tensile stress in the body of the glass.
Because of the compressive force at the glass surface, tempered glass is very resistant to micro-cracks and crack propagation. Not only does this mean that tempered glass can withstand greater temperature and pressure ranges than non-tempered glass, but when it breaks, it will shatter into blunt granules instead of sharp splinters and shards.
You’ll see tempered glass in everything from car windshields to shower doors and even some kitchenware! Ever dropped a drinking glass and have it sound like marbles or ice-cubes crashing to the floor? In fact, broken pieces of tempered glass look a lot like broken ice-cubes; rough but not at all dangerous to touch and pick up.
Why look for tempered glass in a dive mask?
All top quality diving masks will have a tempered glass faceplate or lenses. This feature should be indicated on the mask’s packaging, online product description, or even the mask itself.
Tempered glass is important on a dive mask so that the mask can safely handle the pressure changes at depth and the wear and tear of being routinely bumped, packed, and cleaned. The lenses or faceplate will be less likely to scratch or crack, and if they do, the faceplate will safely shatter into blunt granules, not shards or splinters.
The lenses or faceplates on cheap masks can be made with untreated glass, or even polycarbonate plastic instead of glass, which is prone to scratching and isn’t suitable for much beyond playing in a pool!
2. High-Grade Silicone
The skirt of your dive mask should be made with high-grade silicone. The skirt is the soft, rubbery portion of the dive mask that makes a seal against your face. High-grade silicone is hypoallergenic, very soft and comfortable, resistant to UV damage, and stands up to repeated saltwater and chlorine exposure.
How can you tell if silicone is high-grade?
High-grade silicone means the mask skirt is made of 100% (or nearly 100%) pure silicone. This should be advertised somewhere on the mask’s packaging. You’ll also notice that the skirts on these masks feel very soft and comfortable and won’t have any noticeable odor. If the skirt is clear, you shouldn’t see any semi-opaque, smudgy, or milky spots anywhere.
Why look for high-grade silicone in a dive mask?
The main advantage of high-grade silicone is that it will make your mask last longer. Pure silicone is resistant to ultraviolet, salt, and chlorine damage so these masks can handle literally hundreds of dives.
Pure silicone is also very soft. That means it will make an excellent seal on your face and reduce leaks.
The cheaper alternatives that you’ll often find in hotel gift shops and department stores are silicone blends that also include natural rubber and PVC plastic, which are prone to hardening, cracking, and sun damage over time.
3. Smooth Buckle Ratchets
Ideally, you’ll want a strap that’s easy to tighten on the fly. On a top-quality dive mask, pulling the free tabs of the strap while it’s on your face shouldn’t take much effort.
The ratchet should feel both smooth (with a series of satisfying clicks as the strap moves through it) and secure. A tightened strap shouldn’t be prone to spontaneous loosening! The best ratchets can be adjusted while they’re on your face, sometimes even with an easy-to-use push button.
Tip: Remember not to over-tighten your mask strap! Your straps should be just tight enough to gently hold the mask in place. A too-tight strap is a common culprit behind leaky masks!
4. Robust Frame (Unless Frameless!)
Most dive masks attach the tempered glass lenses or faceplate to the silicone skirt via a plastic frame. On top-quality masks, this frame will feel solid and robust. In some cases, the frame may even be reinforced with stainless steel, though this feature can make the mask heavier.
A well-constructed frame can also be taken apart (for cleaning or to swap in prescription lenses, for example) and put back together without breaking or creating leaky spots.
However, a growing trend these days is the frameless mask, which features a skirt directly molded onto the tempered glass faceplate. No frame required! This design allows for lower volume, greater flexibility, and lighter weight. These masks are also great for traveling because you can crumple the skirt right against the faceplate.
Related Post: Framed Vs. Frameless Masks: Pros and Cons
5. Optical-Grade Glass
What is optical-grade glass?
Standard tempered glass that’s 1-2 mm thick (roughly what you’d get in a dive mask) has a light transmittance of about 84%. You may also notice that tempered glass has a slight greenish tint.
Both of these features are due to the iron content (ferric oxide) in the silica particles (sand) the glass is made from. Not only does the iron block some of the light transmission, but it also imparts the greenish tint. Standard tempered glass typically has a ferric oxide content of about 0.1%.
For improved light transmission (resulting in higher clarity) and color fidelity, tempered glass can be specially manufactured from low-iron silica. Low-iron silica can have a ferric oxide content as low as 0.01% and the resulting glass has over 90% light transmittance (and no green tint).
However, natural sources of low-iron silica are rare and purifying regular glass sand requires intense chemical washing processes. As such, low-iron glass is typically reserved for special applications that require maximum light transmittance and color fidelity.
Some common examples include glass for aquariums and display cases, high-transmittance windows, and of course optical components.
Types of high-grade glass for dive masks
UltraClear Glass
Atomic Aquatics was the first company to produce a dive mask featuring low-iron glass (often termed UltraClear). Their entire lineup today features UltraClear glass.
The core lineup from Atomic Aquatics featuring UltraClear glass:
Other companies have since followed suit. UltraClear options are now available from Hollis (e.g. M1 Frameless Mask) and Scubapro (e.g. Crystal-VU Plus Mask) as well.
ARC UltraClear Glass
The other major innovation in dive mask tempered glass is anti-reflective coating (ARC). Remember how low-iron silica can increase the light transmittance of tempered glass to just over 90%? What about the remaining 10%? That last 10% is reflected back by the tempered glass. And that’s where ARC comes in.
ARC is a very thin (a few micrometers) coating of metal oxides applied in multiple layers to both the inner and outer surfaces of UltraClear glass. The multiple layers of various metal oxides each have different refractive indices that lie between the refractive indices for glass and air or glass and water (depending on which side of the lens the coating is on) for different wavelengths of visible light.
The result is that most visible light (up to 98%!) can pass through the glass. This technology is invaluable to optical applications. But where dive masks are concerned, Atomic Aquatics again led the way, with other companies soon following suit.
Why look for high-quality glass in a dive mask?
The main advantage of UltraClear and ARC glass lenses is the superior vision they offer. Have you ever found that colors are just a bit washed out through your dive mask, especially as you get deeper? That’s because light gets absorbed very quickly with depth, leaving predominantly blue wavelengths. As such, ensuring your mask is letting through all the light it can is a priority for many divers.
Are you interested in underwater photography or videography? Do you do coral restoration work or fish identification that requires you pay close attention to detail? Once you try UltraClear you might never go back to regular tempered glass again!
Do you like to dive in low-visibility conditions, such as very deep (e.g. technical diving) or at night? Then UltraClear ARC will ensure none of the precious light available to you is wasted.
On the flip side, have you ever been bothered by glare in your mask near or at the surface? Do you sometimes see annoying “ghost reflections” in your mask? UltraClear ARC glass eliminates this problem, giving you glass that is nigh close to “invisible”!
6. The Most Important Thing to Look for in a Dive Mask is: A Good Fit With Your Face!
Of course, this is the most important feature of any dive mask. A mask can have all the fancy bells and whistles you want, but if it doesn’t fit you then what’s the point, right?
Once you’ve picked out a candidate mask at your dive shop or have received a purchase you made online, the first thing you should do is a “face-fit test”. Here’s how:
- Move the strap over the front of the mask. Gently press the mask skirt onto your face while holding your breath. Does it stick a little bit? Make sure there isn’t any hair caught under the skirt!
- Inhale a little with your nose. Does the mask stick to your face without you holding it there?
If you answer yes to both questions then the mask skirt is making a proper seal with your face!
A mask skirt that doesn’t seal on your face properly will result in leaks and fogging!
Related Post: No-Leak Dive Mask: How to Get a Perfect Seal
Tip: If you have facial hair, it’s best to shave before doing this test and before using your mask in the water. If you really love your ‘stache, you can improve your seal by rubbing chapstick onto the mask skirt. Just make sure you don’t use anything petroleum-based as this will damage the silicone! Your best bet is to use a product specifically designed for this purpose, such as this mask sealant.
What Else To Look For In A Dive Mask?
Volume
A low-volume mask has been specially designed to minimize the amount of air inside the mask. This means the faceplate or lenses will be closer to your face.
Definitely look for a low-volume dive mask if you’re interested in freediving or spearfishing! Low-volume masks require less air to equalize at depth. As a result, you can conserve your precious oxygen capacity during breath-hold.
Nevertheless, plenty of snorkelers and SCUBA divers also enjoy low-volume masks for their lightweight feel and superior peripheral vision.
Related Post: What is a Low-Volume Mask? (They Aren’t Just for Freedivers!)
Number of lenses
Snorkel masks can have separate lenses or a continuous faceplate window. Which you prefer is a personal decision as neither is inherently better or worse than the other. Low-volume masks typically have dual lenses. Some folks prefer a continuous faceplate if they want their visual field to be as clear as possible (e.g. underwater photographers).
Related Post: Single Vs. Double Lens Masks: A Matter of Taste
Prescription options
Though this feature was once quite rare, more double lens masks these days have the option to include prescription lenses. Folks who cannot wear contact lenses (or prefer not to) now have several models to choose from (this link goes to a selection of double lens masks on Leisure Pro with corrective lenses available). You can swap out the regular lenses in these masks with corrective versions. You’ll just need to know what your prescription is in diopter increments. Some masks even have bifocal options (like reading glasses), which are great for divers who have difficulty reading their gauges.
However, this lens swapping feature cannot work for masks with a single faceplate window.
Tip: If your prescription falls between two of the available diopter increments, pick the lenses with the stronger correction as your eyes are more likely to get slightly worse than better over time!
Skirt opacity
Though the glass and silicone of a high-quality dive mask will block most incoming UV rays, your eyes can still become fatigued in bright sunlight.
A mask with a dark-colored, opaque skirt (as opposed to a clear skirt) will offer your eyes some shade on sunny days. Because I have some hypersensitivity to light, I always prefer black skirt masks. However, other folks prefer clear skirts specifically because they let more light in. This clarity can make the mask feel more “invisible”. Most high-quality masks come in both dark and clear skirt versions.
Purge valve
Some masks have a purge valve on the nose pocket to help you clear the mask if too much water leaks in. Exhaling through your nose will open the valve, allowing the water to drain out without using your hands.
This feature is most useful for SCUBA divers who have difficulty with mask clearing or who have their hands busy (e.g. photographers or researchers). Most well-trained divers with properly-fitting masks will not have to clear their masks often anyways.
The valve can also add some rigidity to the skirt around your nose, which some folks find less comfortable. It can also be prone to leaking if debris gets caught in it. I personally find purge valves on masks kind of gimmicky and wouldn’t recommend them.
Even so, there are divers who swear by their purge masks. Whether it’s because they prefer a more vintage style of mask, or because their mustache makes their mask prone to leaks, some folks appreciate the easier mask clearance that purge valves offer.
Related Post: Purge Valves on Dive Masks, Gimmick or Useful?
What To Look For In a Dive Mask: Takeaway Points
- Tempered glass is an essential feature of any dive mask because it is both durable and safe. Never compromise on this one!
- A high-grade (high purity) silicone skirt will last the longest and make the best seal on your face.
- A reliable and easy to use buckle ratchet and a strong frame will ensure your dive mask is a breeze to adjust and unlikely to break
- UltraClear and/or ARC tempered glass will give you unparalleled clarity and a crisp image free from color distortion, glare, and ghost reflections.
- The most important feature of your dive mask is that it makes a good seal on your face (and as such feels comfortable and barely leaks).
- Other features to consider include mask volume, number of lenses, skirt opacity, prescription options, and purge valve.
A Few Extra Tips!
- Be sure to remove the manufacturer’s coating from the tempered glass before using the mask to reduce fogging (this great article from Girls That Scuba covers multiple methods)
- Use a good anti-fog on the glass before each diving or snorkeling session to reduce fogging (this is the one I prefer)
- If you have long hair, consider using a neoprene strap cover to avoid tangling with the strap!
Disclaimer: Some of the links used in this article are affiliate links (learn more here). That means I may get a small commission if you buy a product after following the link (at no extra cost to you!). If this article helped you in your quest for a perfect dive mask, consider it like giving me a little thank you!
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