The Tusa Geminus Dive Mask's unique 2-window design offers exceptional visibility and low-volume comfort while incorporating TUSA's patented 3-D Strap and Round Edge skirt technologies. A newly designed skirt mounted Quick-Adjust Buckle System further enhances comfort and ease of fit. Simply, the Geminus leads where others will follow. Prescription lenses can be added to the Tusa Geminus 3-D Strap TUSA's patented 3-D strap is a true three-dimensional design that snugly fits against the head's natural curvature. The 3-D strap offers unprecedented comfort and fit unlike standard flat mask straps. TUSA Corrective Lens TUSA Round Edge Skirt Round Edge Skirt TUSA's Round Edge Skirt features a proprietary round edge cross-sectionally shaped skirt. This rounded edge results in a soft fit that suppresses pressure and reduces creasing left on the face. The "planar fit, instead of linear fit" silicone skirt maintains great fit and unprecedented comfort. TUSA Quick Adjust Buckle System Quick-Adjust Buckle System The Quick-Adjust Buckle System incorporates a newly-designed low-profile buckle. The result is a compact, lightweight, technologically advanced mask design that can be easily and quickly adjusted for a perfect fit.