The UM31QB Visio Tri-Ex mask is a revolutionary 3-window design that offers an ultra-wide 168 panoramic view. This amazingly wide viewing angle is achieved by the incorporation of domed side windows and the significant reduction of frame structure around the lenses, increasing the field of vision dramatically over traditional masks. The UM31QB mask gently conforms to the contours of your face. Constructed with pure silicone, this mask has been crafted for divers who want a wide front lens combined with a low volume design.