Phillips Model RG-901 radiation protective glasses offers a stylish wrap-around frame with a rubberized foam lining on the inside. The frame is constructed of high impact TR-90 nylon and features a removable T lock strap for secure fit, as well as internal ventilation ports around the foam to help reduce fogging. This product comes with our standard high quality, distortion-free SF-6 Schott glass radiation-reducing lenses with .75mm lead equivalency. The Model 901 fits best for Medium to Large style heads