1911 RMR BASE PLATE, Mounting base with rear fiber optic co-regulating, fiber optic, rear sight. Uses the same hole and location pin dimensions as all RMR bases. These mounts are built for rugged use and black anodize finished. Also included are the (4x) 6-40 flat-head screws to retain the mount to the slide and (2x) 6-32 RMR mounting screws. Red and Green Fiber optic available. Standard weight: 0.55oz / 15.6 grams