Water-resistant/fog-proof, nitrogen gas-filled. Fully-coated lenses provide maximum brightness, clarity and contrast. Removable lens caps included. Coin-style windage and elevation adjustment under screw-down caps. Generous eye relief. Durable leaf-spring for windage and elevation adjustments. Durable, scratch-resistant, non-reflective matte finish. Bullet Drop Compensating reticle for calculating holdover at longer ranges. One-piece tube made of aircraft quality aluminum