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. Two models are available designed for 1-inch or 30mm tubes. Thumb-Nut 30mm SPR Optics Mount