Designed for AR-style rifles, our SPR (Special Purpose Rifle) mounts are ultra-durable with minimal weight and bulk. Their specialized, sleek design delivers optimal height with a forward cantilever for AR platform rifles. They are constructed of lightweight, strong, aircraft-grade, 6061-T6 aluminum with a durable, black matte anodized finish. Product Features Thumb-nut bolts for turning leverage Optimal height and forward cantilever for AR platform rifles Sleek design for low-profile mounting Four-hole ring design for added gripping power Rugged cross-lock base design for ultimate gripping strength