The Oakley Ballistic Shocktube were tested to withstand the battle field with Impact Technology to meet MILPRF 32432 impact requirements. MIL-SPEC eyewear must remain intact throughtout testing without experiencing any dislodging component or fracture to the lens. High-velocity impact rating also surpasses the ANSI Z87.1 test. Thin Stem technology provides a small frame that is compatibly with over the ear hear protection and comm equipment. Oakley Prizm technology uses formulated dye compounding technology producing a color-tuned lens specifically for shooting to provide enhanced clarity and contrast of targets. TR45 lens brings enhanced contrast to a variety of targets such as steel and cardboard. Ideal during low light or overcast conditions, this lens is balanced for both arid and woodland environments. TR22 lens enhances both targets and terrain, and is best suited for bright light conditions. Important Note: Use care when installing/removing accessory lenses. Scratched lenses ...