TUSA Visio Tri-Ex (M-31) boasts an ultra-wide viewing angle of 168 degrees. Designed and developed by the top engineers at Tabata Japan, the Visio Tri-Ex uses water refraction as an aid to increase the field of vision using 2 domed side-mounted lenses. 168 deg panoramic view through 1 window lens. Patented domed side windows. Reduced frame structure to reduce blind spots. Patented round edge skirt for increased comfort and better seal. Three-dimensional strap for unprecedented fit. Five-position strap angle adjustor for micro-adjustment.