The Barska 3-12x40 AO Airgun Riflescope is constructed to withstand the additional reverse recoil produced by airguns. The AO Airgun Riflescope features an adjustable objective (AO) to adjust for multi-range parallax error. The AO allows the scope to deliver continuous accuracy and precision. There are fully coated optics and a ranging Mil-Dot reticle. The 1" tube comes with scope caps. It is waterproof, fogproof and shockproof. After all, when shooting with an airgun, you don't want the glass to fall out of the riflescope.