Lesson 1, Topic 1
In Progress



The function of the mask is to allow the diver a clear view of the underwater environment since the vision becomes diffuse if the eyes are in contact with the water. As a result of wearing the mask, the objects appear larger and closer to the diver.


Over the years, the mask has undergone many improvements and evolved in many ways. This evolution resulted in different manufacturers of masks and a wide variety of brands and models. The mask is formed by one or two glasses (lenses) and a soft “body” that adapts to the diver’s face. The assembly of these two elements is done through a solid and indeformable structure, to which a strap is fixed that allows easy adjustment of the mask to the face.

Bi-lens and mono-lens masks

Initially made of rubber, currently, the most used material in the body of the mask is silicone (usually black or transparent), a more durable material. Perfect grip on the face is achieved through a soft edge, with a configuration that increases the grip surface and helps make the mask watertight with the air pressure inside. At the bottom of the nose, there is no inner edge, so the expulsion of water from the inside of the mask can be done easily.

The increased field of view is obtained by increasing the dimension of the lens (usually mono-lens masks) by increasing the internal volume of the mask, or by approaching the lens of the eyes (two separate glasses), a solution increasingly used by manufacturers for allowing to draw invoking masks.


For those who wear glasses there are two options:

  1. They may wear masks to which the corrective lenses are glued internally, or
  2. Masks whose simple glasses are replaced by lenses, with the necessary correction of diopters because they are in contact with water.

The assembly of these elements must be made on the solid and indeformable structure of the mask, so as not to suffer oscillations in relation to the diver’s eyes.


The adaptation of the mask to the face should be comfortable (it should not be too tight, but only fair) so that it can be used for long periods. In addition, to allow easy compensation, the part surrounding the nose should be projected out, so that it is easy to tighten the nose with your fingers.

The mask should be placed so that the edge does not rest on the hair or on the hood of the suit, thus preventing the entry of water.

It is easy to understand that buying a mask requires special attention and is related to the shape of each other’s face. The model that is good for the diver “A” can be terrible for diver “B”. Therefore, the choice should be taken care of and it is very important to try the mask before buying. Two tests should be performed:

  1. Watertightness: Touch the mask lightly to the face and inhale through the nose. If the mask is attached to the face and adheres for some time, without falling, its water tightness is guaranteed.
  2. Comfort: To test the convenience, you must compress it against the face and make sure that no part becomes uncomfortable or painful, namely the edge and the surrounding area of the nose.

Regardless of the preferred mask type, the choice should take into note the facial morphology of each diver and the following qualities:

  • Have a perfect grip on the face, to be watertight.
  • Be comfortable, allowing prolonged use.
  • Allow easy compensation manoeuvres.
  • Have a tempered glass and with good viewing angle.
  • Have an indeformable part for fixing the lenses.
  • Have as low an internal volume as possible.


The mask is a fragile piece and it is advisable to keep it in a plastic box. This protects it from inadvertent falls or blows and contact with other corrosive substances, such as petrol or other products that attack rubber or silicone.

Maintenance is very important but simple: wash it very well with fresh water at the end of each dive, letting it dry in the shade.