Nikon Inline XR 3-9x40 APG BDC300 Precise, hand-turn 1/4-MOA click adjustments-Positive-click reticle adjustments get you zeroed in quicker and maintain your setting even with heavy recoil. Nikon's patented BDC 300 reticle-This patented, trajectory-compensating reticle integrates unique, easy-to-see ''ballistic circles'' that provide instant aiming pointsand take the guesswork out of holdover at longer ranges. Multicoated optical system-Bright, multicoated optics deliver up to 92-Percent light transmission. Five-Inch of constant eye relief w/ Quick Focus Eyepiece-keeps your brow safeeven with the heaviest slug loads. Waterproof, fogproof, shockproof-Nitrogen-filled and O-ring sealed.