Fits onto AR15 Carbines/M4 with the carbine length gas system using the GI Handguard Cap and Delta Ring; Provides the steady platform attaching: Optics, Lasers, Flashlights, Verticle Grip, Bipod, and other accessories; Large ventilation holes to help keep the barrel cool; Easy to install with four Allen head screws and the provided mounting tool; No gunsmithing required, drop-in fit; All aluminum construction; Laser engraved rail markings (white); Black anodized finish; NcSTAR One Year Warranty