Features Include: Designed to give a factory installed appearance to the rifle. Proprietary replacement barrel nut included with rail that allows for easy installation and elimination of barrel nut timing issues. Mounts on barrels with low profile gas block, or can replace fixed front sight (basic punch, hammer) with a low profile gas block (not included). Comfortable round shape. Sturdy, lightweight free float design. Improves accuracy and provides exceptional airflow to keep barrel cooler. Flush mounted top rail for a monolithic appearance. Lightning fast configuration changes. Uninterrupted mounting surface for optics or other accessories. Improves comfort and ease of shooting while allowing for personal modification with optional rail accessories (rails & bumpers). Customize for specific applications; Add more rails as additional accessories are needed; Mix full length and short rails and bumpers to suit. Proprietary clamping system for rigid, secure attachment. Mil. Spec. Type III anodized 6061 aluminum construction. Mil. Std. 1913 Picatinny rail dimensions. Fits all M4/AR15/M16 variants. Combat durable.