Warne Vapor rails are designed to offer shooters an affordable and reliable mounting platform manufactured for your specific firearm. The V489-15MOA offers 15MOA of elevation built in for longer distance shooting. - Fits: Ruger American Rimfire w/6-48 screw receiver - Precision CNC machined from 6061/T6 aluminum - Mil-Spec hardcoat anodized finish for abrasion and corrosion resistance. - Self centering tapered T-15 Torx screws. - Fits Picatinny & weaver style rings and are NATO-STANAG compatible. - 15MOA - Tapered 6-48 Screws