Tusa Visio Tri-Ex Adult Combo Snorkel SetVisio Tri Ex Adult Combo Snorkel Set The VISIO TRI EX adult combo includes the UM 31 Visio Tri Ex mask and the USP 250 Snorkel. The UM 31 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