The KAC Carbine Free Float RAS (Rail Adapter System) features full length mil-spec M1913 Picatinny rails at the 12, 3, 6, and 9 o'clock positions compatible with any rail-mounted accessories.The KAC Carbine Free Float RAS free floats the barrel allowing for consistent barrel harmonics upon firing increasing accuracy potential. Kit includes three KAC 11 Rib Rail Panels.Specifications: Total Length: 7 3/16 Picatinny Rail Length: 6 3/16 Weight: 13.9 oz. Free Float: Yes Material: Aluminum Finish: Black Anodizing P/N: 20208Rifle Requirements: This Free Float RAS will work with firearms with a carbine length gas system and standard A frame front sight. Disassembly of the rifle's gas system and removal of the factory barrel nut is required. This RAS uses a proprietary barrel nut that may be installed using a standard AR-15 armorer's barrel nut wrench (sold separately). For AR-15/SR-15 based platforms only; not compatible with SR-25 variants.