Without sliding the mask strap over your head, put the diving mask on your face. Breathe in lightly through your nose, hold your breath. The mask is aspirated due to the vacuum. If it fits optimally to the shape of your face, it will ideally remain adhered as long as the vacuum is maintained. Air may not penetrate nor should the mask pinch in any place. It should not be too close to the eyebrows and the corners of the eyes, the frame should not press against the nose, which should have enough space in the nose pocket in any case (no banging). Pressure compensation must be feasible in the inner space of the mask.
The mask strap
Its width and length should be adjustable to ensure a good pressure distribution and maximum wearing comfort. The back of your head is flat or prominently arched? The flexibility of the mask strap solves that problem at its best. And last but not least: Can the adjustment mechanism be operated in an uncomplicated manner? After all, under water you do not want to pull out the instruction manual, in order to be able to promptly make adjustments to your diving mask.
The recommended material here is silicone. Relief for uncomfortable pulling of the hair is provided by neoprene covers that can be slid onto the straps or by exchanging them with neoprene mask straps.
The correct fit
of the mask should be tested a second time with the regulator or the snorkel in your mouth! The mouthpiece changes the muscle tension in the face, so that the border that fitted evenly might suddenly not be well-sealed anymore and water may seep in.
Before the first use
remove the production-related oily film produced by suppressed silicone gases from the inside of the lens, or else the mask will fog up.
First possibility: Rub some toothpaste (no gel) on the lens with a clean cloth, let it dry, and rinse it with warm water. Possibly repeat several times.
Second possibility: Fill the diving mask with Coke, let it stand overnight, rinse with fresh water.
Against fogging of the mask
Rub some saliva with greaseless, clean fingers on the inside of the dry (!) lens. Rinse it briefly with water. Oh, wonder of nature: Sugar molecules and fatty acids prevent the condensation on the glass.
High quality masks are already equipped with a chemical film protecting from fogging.
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