The mask is probably the most important piece of equipment. It enables us to see underwater and as we are visual predators, without it we are lost. The diving mask differs from swimming goggles in that it covers your nose enabling you to equalize the airspace within the mask.
FIT: The most important thing with masks is that they fit properly. Everything else is secondary. To check if a mask fits properly you put it on your face (without the strap) and suck in through your nose. If the mask sucks onto your face it fits. If it does not it doesn't fit. Simple. Also check that the frame isn't pushing on your face anywhere, especially across the bridge of the nose, as this will be agony after several hours in the water.
MATERIALS: Ensure that your masks skirt is made of 100% crystal silicone. This forms a much better seal on your face than the old rubber masks and doesn't perish which extends the life of your mask considerably. There are several cheaper substitutes on the market such as Silitex which is not silicone and does not create anywhere near as good a seal. The mask lens must be made of tempered glass for obvious reasons. You can check this by looking at the bottom of the lens, it should have TEMP or CE stamped on it. Lastly check the strap buckles, do they look strong and can you get parts if they break? It is however worth noting that the first thing a lot of experienced spearos do when buying a new mask is rip off the buckles and tie the strap straight onto the mask frame. This eliminates several failure points and makes in the water repairs much easier.
FIELD OF VISION: Obviously field of vision is very important to a hunter. Try and find a mask that doesn't give you tunnel vision and that doesn't have a big black patch between your eyes. The closer the lens is to your face the greater your peripheral vision will be. Also check what its like looking down. Would you be able to see your weightbelt? What would it be like trying to see what you're doing while dispatching a fish?
VOLUME: When you look at specialist freediving masks they will often claim to have extremely low internal volumes. This means that it takes less air from your lungs to equalize the mask. Realistically though 90% of modern masks are low volume and volume should be one of the last things a spearo considers when picking one. All of the masks for sale on this site would be considered low volume.
COLOUR: You should always choose a mask with a black skirt. Because we are going from a very bright environment on the surface to a relatively dark one under the water, the black skirt which blocks out light on the surface allows our eyes to adjust to the darker underwater environment much quicker. The black also attracts light further enhancing vision (this is why sportsmen sometimes put charcoal under their eyes). Light coming in through the side can also make funny reflections on the lense.
TINTED LENS: There are a number of masks on the market that have tinted or mirrored lens. The idea is that skittish fish will not be spooked by seeing your eyes. The downside of these lens is that they often darken your vision which makes them much more popular in tropical environments and a bit too dark for most NZ diving.
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