Ncstar 1" Scope ring mounts designed to fit all standard 3/8 rim-fire rifles and airgun dovetail rails. Dovetail rings have hexagon shape mounting nut with holes for torquing with Allen key wrench. Black Hard Anodized Aluminum Construction. Rings sold as a Pair. Optic Centerline Height: 0.9". Ring Overall Height: 1.9". Mounts onto 3/8" Dovetail rails.