Nikon 6729 ProStaff 4-12 x 40 Black Matte Riflescope (BDC) polymer, aluminum Imported Compact riflescope with 4 to 12x magnification and 40mm objective lens Fully multicoated optical system transmits up to 98 percent of available light Zero-reset turret with spring-loaded adjustment knob; 3.7 inches of eye relief Nitrogen-filled, O-ring-sealed housing for waterproof, fogproof performance BDC reticle; quick-focus eyepiece; measures 14.1 inches