Made of Grilamid TR 90, a homopolyamide nylon characterized by an extremely high alternative bending strength, low density, and high resistance to chemical and UV damage. Hydrophilic rubber ear and nose pieces for a no slip fit. Adjustable ear pieces for a customizable, comfortable fit.Fototec lenses with variable tint technology T Vadjust rapidly to changing light conditions for superior clarity and protection. In bright sun, microscopic photochromic particles embedded in the lens react to UV rays darkening the optics so you'll never squint. Then with cloud cover, the particles return to their previous state letting through more light.