The Vortex Crossfire II 4-12x50 AO CF2-31039 is clearer, tougher, and brighter than ever, outperforming other similarly-priced riflescopes. Built from aircraft-grade aluminum alloy ensure it is virtually indestructible to recoil and harsh conditions. Argon gases are filled in the housing to guarantee it is water and fog proof. Fast focusing eyepiece ensures you hit your target and resettable MOA turrets ensure optical excellence. The Vortex Crossfire II 4-12x50 AO features lenses that are fully multi-coated to deliver excellent color fidelity, superb resolution, and clarity.