Hollis M-1 Scuba MaskHollis M 1 Mask raises the bar for optical quality and distortion free vision. The extra crystal clear Saint Gobain Diamant tempered glass single lens is valued for its attractive appearance and optical qualities. M 1 Mask provides a wide field of vision with a low internal volume making it extremely easy to clear. The 100% pure silicone double feathered edge skirt and wide split style mask strap combine for a perfect seal and comfort on the face. The