The new PROSTAFF Target EFR 3-9x40 is designed for .22 LR, Air Rifle and other applications where the versatility of focusing at extended ranges � both close and distant - is desired. Fully Multicoated Optical System: Provides optimum light transmission and maximum brightness from dawn to dusk. Waterproof/Fogproof/Shockproof: Nitrogen filled and O-ring sealed. Zero-Reset Turrets: To simplify field adjustments, Nikon has integrated this feature into all new riflescopes. Just sight-in as usual, then lift the spring-loaded adjustment knob, rotate to your �zero�, and reengage. Field adjustments are now as simple as dialing-in your subsequent ranges. Quick Focus Eyepiece: Allows the shooter to instantly bring the reticle into sharp focus.