The 556 SWITCH(TM) Rail - B.A.D Edition is the result of a special collaboration between Battle Arms Development, Inc. and Fortis Manufacturing. This unique design provides a proprietary clamp system allowing easy removal of your B.A.D rail. This continuous, lightened picatinny rail is machined from 6061-T6 aluminum and features M-LOK at the 3 & 9 o'clock and Keymod at the 6 o'clock positions. Locking handle: 7075-T6 Aluminum Internal diameter: 1.34" Rotation limited QD sockets 4140 heat treated barrel nut (1-7/16 x 16 T.P.I.) Clamp torque setting 20in lbs Spanner wrench needed to torque barrel nut to spec (not inclu Mfg: Battle Arms Development Inc.