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