Aggressive design ultra light 5.5 free float hand guard.Its unique design features a very slim profile (1.375 id) that still allows for the installation of a sound suppressor of 1.40 in diameter and smaller to tuck inside of the handguard when used with an exact length 6 barrel.Works with 223/5.56 and 9mm calibers.Handguard does not require timing and installs with a standard wrench.(will not fit 308 models)Rails: PicatinnyMaterial: AluminumFinish: AnodizedFree Floating: Yes