The bsa sweet scopes use trajectory compensation technology that was originally designed for military sniper.They feature a quick change turret system specially calibrated for multiple grain weights for the calibers:.17hmr,.22lr,.223,.243,.270.The bsa sweet 17 ao features a long eye relief for comfortable viewing, an adjustable objective, as well as the preferred 30/30 reticle.It comes standard with 2pc dovetail rings and fully coated anti-reflective lenses all in a one-piece aluminum housing.Adj Size: .25 MOAMagnification: 3-9xObjective: 40mm AOField Of View: 34.20-11.50 ft @ 100 ydsEye Relief: 3"Tube Diameter: 1"Length: 12.30"Weight: 22.30 ozReticle: 30/30 DuplexParallax Adjustment: 7.5 yds-InfinityParallax Adjustment: 7.5yds-InfinityProofs: Waterproof, Fogproof, ShockproofCoating Type: Waterproof, Fogproof, ShockproofOptic Coating: Fully CoatedOptic Coating: Fully Coated