Building off of the patented TRX Extreme design that revolutionized rail-based handguards, the Alpha Rail utilizes a new, low-profile locking mechanism and affords unparalleled strength and stability. Features: Genesis of modular free float rails. Disperses heat and runs cooler than other close to the barrel. Comes with two 2" and one 4.2" detachable rails and all mounting hardware Technical Specifications: Machined from hardened aircraft aluminum with stainless steel components. Finished in MIL-SPEC hardcoat anodizing. Works with standard AR15/M16 barrel nut No barrel nut included. Note: Alpha rails do not work with the TRX Barrel Nut or TRX Barrel Wrench.