Nikon Prostaff 7 5-20x50 SF Waterproof Black Riflescope with BDC Reticle Fully multicoated lenses for bright images and well-balanced colour Quick-focus eyepiece and generous eye relief ensure easy and comfortable operation Broader range of elevation and windage adjustments in 1/4 MOA click-stop moves Spring-loaded, instant zero-reset function 30mm tube diameter and 4x zoom ratio