AXCC-GH4655

Modern-day masks may be among the most distinctively styled and individualistic pieces of equipment that you’ll find in a dive center. Yet, as different as they may appear, all masks (even the old porthole-style “frogman” masks that you see in 1950s movies) do three basic things:

1、Masks add an air space between your eyes and the water. This is not only more comfortable; it is physically necessary on order for your eyes to see and focus properly. Your eyes focus naturally in air, so without an airspace in front of your eyes, things will look fuzzy underwater. The airspace provided by a mask restores clarity (and if you normally wear eyeglasses, many dive masks are available with prescription lenses).

2、Masks provide a pocket through which you can squeeze your nose shut with your fingers. Why would you want to do that? Because the easiest way to equalize (or “clear”) your ears is to be able to squeeze your nostrils closed and fill the airspace in your ears by gently blowing against the closed nostrils. This “pushes” air from your lungs into airspace in the ears, just like equalizing your ears when you’re driving at altitude or flying. After you’ve been diving for a while, you’ll probably become adept at clearing your ears without even touching your nose. But during the first few dives of the season, or if you’re even the slightest bit congested, you’ll want to be able to squeeze your nose shut, and a flexible nose pocket is necessary to allow you to do that. For that reason, choose a mask design that provides easy access to gently pinching your nose.

3、Masks provide a means of equalizing pressure and expelling collected water. Many non-divers assume that the reason a dive mask encloses the nose, as well as the eyes, is to keep water out of your nose and negate any need for a nose clip. Masks designs certainly do this, but that’s not the real reason your nose in contained in your mask – it’s just a handy side benefit. The real reason for having a mask that encloses your nose is so you can exhale through your nose into the mask space, adding air to equalize the air pressure within the mask to match the hydrostatic pressure of the water pushing against the mask from the outside. If you couldn’t do this, the mask would quickly develop “squeeze” and grow uncomfortable as you went deeper. In addition, if water gets in and accumulates in the bottom of your mask, you’ll want to be able to clear it out easily. With most masks, you simply exhale through the nose while tilting the mask slightly so the water gets pushed out past the flexible skirt edge at the bottom of the mask. Some masks incorporate a one-way purge valve in the mask’s bottom; with these, you don’t even need to touch the mask to clear it. You just tilt your head so the purge is at the mask’s lowest point, exhale through your nose, and the water all drains out of the purge valve.

All dive masks today have the potential to do their principle jobs – letting you see, letting you equalize, and clearing easily. But no mask can do any of the three unless it fits your face. Different makes and types of masks fit different facial types better. Your retail dive professional will have the experience with which masks favor, say, a narrow face and which ones are best for people with prominent cheekbones, or broader faces. In addition, some manufacturers offer different sizes of the same basic mask model to better fit individual faces.

The time-honored method for checking fit on a mask is to hold it to your face without using the strap to secure it, inhale just slightly through your nose to create low pressure within the mask, and then hold your breath and see if the mask will cling to your face snugly. A mask that falls off immediately, or in just a few seconds, is a mask that is leaking air at one of its edges, and if a mask leaks air, it will leak water, as well.

Once you find an assortment of masks that will stay on your face, there are a variety of other tests that you can do to see if your mask and your face can form a perfect match. One is to hold the mask gently against your face and exhale through your nose. If the air only leaves the mask in one or two places, those might be areas where the mask seal is not robust enough for your particular face. But if the soft edge of the mask’s skirt flutters more or less equally all the way around, then that’s another indication that you have found a good match.

The most important test, though, is to have someone knowledgeable, such as a staff member at your local dive center, closely inspect the way the mask sits on your face when you are wearing it. He or she will not only be looking for a good seal; a knowledgeable professional will also look for other nuances:

• Are the eyes centered naturally on the lens area? Is the skirt edge crossing your hairline or eyebrows, creating a potential leak point?

• If you’re a guy who wears a moustache, does this particular mask skirt have enough seal area above your moustache to keep you from being troubled by seepage there?

• And is this type of mask going to complement the sort of diving that you will primarily do?