This genesis of modular free-float rails has arrived building off the trx extreme design.The alpha rail utilizes a low-profile locking mechanism which offers unparalleled strength and stability.The alpha rail disperses heat and runs cooler than other close-to-the-barrel rail systems.With unlimited mounting options and greater heat dispersion the alpha railsets comes with three detachable rails and all mounting hardware.Works with standard ar15/m16 barrel nut (no barrel nut included).Includes two 2" and one 4.2" detachable rails and all mounting hardware.Note: alpha rails do not work with the trx barrel nut or wrench.Rails: 1 Fixed/3 DetachableType: Railed ForendFirearm Type: RifleFirearm Model: AR15/M16Material: AluminumFinish: AnodizedFeatures: 8 Angles Of AttachmentPositions: 8Free Floating: Yes