The strongest and most indestructible two-window mask ever. So durable, it has Lifetime warranty against frame breakage. This strength is the result of an internal frame (called the subframe) that is moulded directly beneath the surface of the silicone rubber skirt. This subframe provides incredible strength and rigidity as well as eliminating the bulky external plastic frame in other masks. A stainless steel lens retainer locks the lenses in place and provides added strength to the nose bridge area of the mask. A wide field of view and great fit completes the combination of function, style and durability.