Sons of Liberty Gun Works Drive Lock M-Lok 13. Featuring a titanium barrel nut full length M-LOK attachment slots at 3/6/9 two integrated steel QD (limited rotation) sockets and ''Fast Slots'' beneath the 12 o'clock rail for zip ties for cables the M89H is built for end-users who demand the rigidity the 89 series of handguards is becoming widely known for. Maximum strength maximum mounting space and weight savings material choices make this one of the finest fighting handguards available to date. Specifications for Sons of Liberty Gun Works M89 Heavy MK10 Rail: Manufacturer: Sons of Liberty Gun Works Color: Black Finish: Anodized Gun Make: AR Platform Gun Model: Universal Gun Type: Rifle Gun Rail: M-LOK Package Contents: Sons of Liberty Gun Works M89 Heavy MK10 Rail M89H Rail Barrel Nut Barrel Nut Wrench Lock-Up Components Sons of Liberty Gun Works M89H13: Drive Lock M-Lok 13