The NcSTAR 45 Degree Off-set Rail allows accessories to be mounted. It is great for lights, lasers, and micro-dots sights. It keeps accessories off to the side so they don't interfere with vertical grips, handguards, or optics. The ergonomic design gives easy access to on/off switches for Flashlights, Lasers, or Red Dot sights. An Allen bolt secures the mount to weaver/Picatinny style rail. The rail is constructed of high grade aluminum.