Single Some people prefer a single lens because they believe the bar on two lens masks across the bridge of the nose will be distracting. This is generally not a problem because unless you deliberately try to look inwards you will not see it. Once you forget the bridge is there you will not notice it. The true benefit of a single lens mask is that they tend to be higher volume, which suits people with larger noses or a protruding forehead.
Double Double lens masks are generally able to fit closer to the eyes, which allows greater visibility. The two lens mask has a low internal volume which requires little effort to clear.
Side Windows The side windows on a mask provide enhanced side vision. A mask with side windows does have a larger internal volume, which will require slightly more effort to clear.
Mask Skirts
Rubber Rubber is rarely used in modern masks as other materials listed below offer either lower costs or greater comfort and durability.
PVC PVC is a very inexpensive plastic material that is generally used on very inexpensive masks. It tends to be relatively hard and uncomfortable against the face and can lose shape quickly.
Silitex Silitex is a combination of silicon and PVC. It is softer and more comfortable than PVC and is suitable for the casual snorkeller or holiday maker.
Silicon - Black or Clear Silicon is the best material for a mask skirt. It is very soft compared to other materials making for a better fit and greater comfort. Silicon holds its shape very well and is extremely durable. Black silicon is the product of choice for some snorkellers/divers although clear silicon is more popular. They are generally the same quality. Black silicon lets in less light, which some people find less distracting and is more popular with spear fishermen. Some people prefer the more open feeling and the cosmetics of clear silicon. Clear masks also have a wider range of colour choices for the mask frames.
