IST M99 Seal Twin Lens Dive Mask LIGHTWEIGHT  Low-volume design minimizes drag and doesn't weigh you down. INTEGRATED DESIGN  Skirt is molded directly onto the frame. ADJUSTABLE FIT  Swiveling buckles and adjustable strap are easily modified. COMFORTABLE  Hypoallergenic skirt is super-soft and great for extended wear. TWIN LENS  Dual lenses sit close to the face for minimal view obstruction.