First issued by Vuarnet in 1999. Frame is injection molded nylon, with side vents to eliminate fogging. Four lenses are available, from light brown PX2000, which accomodates everyday use, to intensely dark PX5000, which is specifically designed for high-altitude climbing on glaciers. All filter out 100% UVZ, UVB and UVC radiation. Multi-layered anti-reflective coatings eliminate glare and bounce-back light. Lenses are glass, ground and polished on both sides to ensure distortion free vision, and are heat tempered for impact and scratch resistance.