Changing outdoor light conditions doesn't require changing eyewear anymore. SmartLens protective eyewear lightens and darkens with rise and fall of outdoor light conditions, transitioning from light to dark in less than 20 seconds (allowing just 22 percent light transmission) and dark to light in less than 3 minutes (allowing 77.5 percent light transmission). Polycarbonate, photochromic, abrasion-resistant lens absorbs 99.9 percent ultraviolet. Half-frame design also features a soft adjustable nose bridge, nylon brow and magnesium alloy spring-hinged temple for a flexible fit. Safety eyewear meets the traffic signal requirements of ANSI Z80.3 -2008 and the High Impact Requirements of ANSI Z87.1-2003.