Primary Arms Basic Scope Mount for 30mm / 1-Inch Scope Tubes BASIC SCOPE MOUNT: Works with 1913 Picatinny mounting and similar "flat-top" platforms. SIZE: Fits scopes with 30mm tubes, or use the included 1-inch adapter shims to mount a 1 inch scope. RUGGED AND DURABLE: Constructed of aluminum with durable matte black anodized finish.