The Action EX line is aimed at hunters who want traditional Porro style glasses but with all the waterproof, fogproof and shockproof attributes of a Nikon All Terrain Binocular. Nikon's exclusive Eco-Glass, made without lead or arsenic, is used to manufacture Action EX lenses and prism systems, resulting in a high quality glass that is also lighter in weight. The 50mm objective lens assures the best in light gathering capability.