The rubber that was used in mask skirts years ago made the wearer feel as though they were looking through a tunnel because the rubber blocked any of the illuminating lights rays. Changing the color of the rubber to white or lighter shades of blue helped alleviate this tunnel vision somewhat but there were other factors that made rubber less preferable for use in mask skirts and straps. Prolonged exposure to heat even lower temperatures caused deformation and even shrinkage of the rubber. Higher temperatures caused obvious melting. Ultra Violet rays, exposure to Oxygen and exposure to chemicals found in pool environments such as chlorine also aided in the degradation of rubber making it become brittle, develop cracks and lose its elasticity. The life of a snorkeling mask using natural rubber was shortened with every use. Avid snorkelers and swimmers using swim goggles with natural rubber skirting could expect to have to repurchase their mask or goggles after as little as a season of use.

A Synthetic rubber product called silicone began replacing natural rubber in masks somewhere around 30 to 35 years ago. It was found that silicone was more resistant to the elements. It was more heat resistant as well as more resistant to chlorine damage from constant use in pool environments. It also showed better resistance to the damaging caused by Ultra Violet light rays. The early silicones used were cloudy but allowed light to penetrate which took away a bit of the tunnel vision associated with natural rubber mask skirts. In a relatively short period of time these cloudier silicones were replaced by clearer versions which is what is found everywhere in the snorkeling world today. The silicones are still subject to degradation but the severity of degradation has been greatly diminished. Silicone exposed to oxygen does begin to become cloudy and opaque but this is more of a cosmetic degradation rather than affecting the elasticity of the material.

Storing your mask in an environment totally devoid of oxygen such as a glass enclosure pumped full of nitrogen will take care of that should it be a concern. For those of us who lack the resources and the funds for such a cure could simply store their masks in a couple of airtight freezer bags with some commercial oxygen absorber packs thrown in for good measure. Care should also be taken when storing the mask to make sure that it is not stored touching natural rubber products. The natural rubber gets jealous and begins to leech its color into the silicone.