TUSA M1007S Paragon S single-window mask offers Reinforced TRI-MIX frame, Freedom Technology with Fit II, and the UV 420 Lens Treatment with AR and CrystalView Optical Glass which helps you dive with eye protection and ultimate clarity. TRI-MIX Frame. Freedom Technology with Fit II. UV 420 Lens Treatment + Anti-Reflective Lens + CrystalView Optical Glass. Angle Strap Adjustor with Side Hold. Offset Buckle.