Building off of the patented TRX Extreme design that revolutionized rail-based handguards, the Alpha RailA(R) utilizes a new, low-profile locking mechanism and affords unparalleled strength and stability. Features: a Genesis of modular free float rails. a Disperses heat and runs cooler than other close to the barrel. a Comes with two 2" and one 4.2"detachable rails and all mounting hardware Note: Alpha rails do not work with the TRX Barrel Nut or TRX Barrel Wrench.