Nikon ProStaff 3-9 x 50 Black Matte Riflescope (BDC) Compact riflescope with 3 to 9x magnification and 50mm objective lens Fully multicoated optical system transmits up to 98 percent of available light Zero-reset turret with spring-loaded adjustment knob; 3.6 inches of eye relief Nitrogen-filled, O-ring-sealed housing for waterproof, fogproof performance BDC reticle; quick-focus eyepiece; measures 12.5 inches