New Tilos Single Lens Panoramic View Scuba Diving & Snorkeling Mask with Purge (Trans Blue) Patented innovative Panoramic technology allows the glass joint to appear invisible when worn by the user, creating a truly uninterrupted panoramic view Patented channeled skirt design directs purged bubbles away from view Tempered glass lenses Crystal silicone skirt and strap With Purge Valve