The MFR Rail Systems from Daniel Defense utilize the M-LOK attachment system for incredible weight savings as well as superior cooling, ergonomics, and modularity while maintaining the strength and durability expected from Daniel Defense. M-LOK attachment points are located along 7 positions on the rail and feature an uninterrupted 1913 Picatinny rail on top. Ambidextrous sling swivel attachment points are integrated into both the left and right side rails. Its sleek bolt-up system increases strength and reduces the overall diameter of the rail making it easier to control, all while utilizing our Bolt-up System barrel nut. Anti-rotation tabs come standard for ease of installation and alignment. The MFR can be used with a pinned low-profile gas block on pistol, carbine, mid-length or rifle length gas systems..