RugerA(R) Rapid Deploy folding rear sight provides windage adjustability and pairs with the A2-style, F-height, elevation-adjustable front sight for a solid, reliable aiming system. Made from 7075-T6 hard-coat anodized aluminum forgings, shot-peened and proof-tested 9310 steel bolt, and 8620 steel bolt carrier. The inside diameter of the carrier and gas key are chrome plated and the key is staked for longevity. Barrel nut and delta ring allow easy, one-person service of the heat-resistant glass-filled nylon handguard. The design accepts most standard carbine-length handguards. The barrel nut uses a standard wrench. Gas block is located at a carbine-length (M4) position for Mfg: Ruger