There's no question on the toughness and brightness of the Vortex Crossfire II 4-16x50mm AO Riflescope. This rifle scope engineered by the geniuses at Vortex features long eye relief, a fast-focus eyepiece, fully multi-coated lenses and resettable MOA turrets. The Vortex Crossfire II 4-16x50mm AO Waterproof Rifle Scope has a hard anodized single-piece aircraft-grade aluminum tube that is nitrogen purged and O-ring sealed for waterproof/fogproof performance. Maximize alignment and improve your accuracy with the Vortex Crossfire II 4-16x50mm AO Riflescope w/ Dead-Hold BDC Reticle for optimum visual performance.