This is the Mares X-Vision Ultra Liquidskin Mask for Scuba Diving - Optional Prescription Lens Options Available below. (Also see Item code RX017) Features: Ultra-clear face (clylwcyl model, clblwcbl) Gold mirror lenses to increase visibility in murky water (gogrkgrk model) Silver mirror lenses to reduce reflection in shallow water or sandy bottoms (sigrkgrk model) New moulded bi-silicone face piece for improved fit and comfort Hydrodynamic design Small ribs around the nose to relieve pressure 20% larger field of vision than the previous version Bi-silicone strap shaped like an "x" shape Please note there will be an additional 2 to 3 days processing time for most RX lenses Some prescription lens increments for left & right eye are no longer available. The X-Vision Ultra diving mask is made of bi-silicone with a large field of vision. 8 attractive colours, 2 mirrored versions, winner of the reddot design award. Excellent mask for exciting scuba diving.Returns are not accepted for used lens. Only unused lens are eligible for return with store credit.