Lightweight machined aluminum forearm combines the accessory mounting versatility of a quad-railed forearm with a “smooth ” un-railed area for support hand comfort to aid in enhanced weapon control. Integral full-length Picatinny top rail plus forward 2.5" rails on the sides and bottom offer plenty of attachment space for lights lasers optics backup sights and other accessories. Modular design accepts a variety of bolt-on YHM accessories available below. Smooth areas are drilled and tapped to accept Add-On Rails for additional accessory mounting options. Side and bottom rails have receptacles for Threaded Swivel Studs; RIFLE version also accepts YHM Forearm End C Mfg: Yankee Hill Machine Co. Inc. SPECS: Aluminum mil-spec hardcoat anodized matte black. Carbine – 9¼” (23.5cm) OAL 2½” (6.4cm) diameter. 12.4 oz. (352g) weight. Fits AR-15/M16 with carbine-length gas system. Rifle – 12½” (31.8cm) OAL 2½” diameter. 16.6 oz. (471