Centurion Arms LLC is happy to announce the C4 MLOK(R) rail.C4 MLOK MID CUTThe MLOK C4 rail system is based off the patented quad rail version. It is a lightweight, rugged, 2-piece free float rail that when installed gives the uppers a continuous 12o'clock rail and MLOK slots for the 3,6, and 9 oa (TM)clock positions. The C4 system is the lightest and most rigid rail that clamps to a standard barrel nut on all AR15, M4, and M16 type weapons systems. This design allows the installation of the rail on an upper assembly without removing the front sight post or permanently attached muzzle devices.FeaturesMaterial: 6061 T6Finish: type 3 hard coat anodizedWeight: 8.9 oz with screws --- 1.1oz more with standard barrel nutLength: Top 9 1/4in Sides 11 1/2in Bottom 10 5/8inHeight: 2.38Inside diameter: 1.37Rails: 1913 spec railFasteners: grade 8 bolts with phosphate finishMADE IN USA