Every bit of air is extremely important in freediving, because in freediving there is no air supply! Therefore, it is advisable to keep the air in your lungs exactly where it is, and not to waste it unnecessarily, for example to equalize the pressure in the mask. It is not possible to avoid pressure equalization in the mask, but at least you can reduce this problem to a minimum with the right freediving mask.
Freediving masks with small inner volume
Large, bright masks with wide lenses for a wide viewing angle may be excellent for scuba diving, but they are no good as freediving masks.... read the whole description