JMac Customs ST-7 Skeletonized Tube for Compact M4 Stocks for SAM7SF Black. (With proper folding adapter) Some M4 style stocks use tension tabs designed for standard buffer tubes to mitigate movement. These will work on our Skeletonized Tubes however you may experience some wiggle. Requires a mount or folding mech to install Attaching a stock to a pistol makes it an SBR and requires NFA approval. You are responsible for knowing and following your local/state/federal laws JMac Customs LLC is not responsible for the end users misuse of our products. FM-SM-1913 - 1913 Folding Mechanism JMac Customs LLC is not responsible for the end users misuse of our products. Specifications for JMac Customs ST-7 Skeletonized Tube for Compact M4 Stocks for SAM7SF: Manufacturer: JMac Customs Color: Black Features of JMac Customs ST-7 Skeletonized Tube for Compact M4 Stocks for SAM7SF Fits most mil-spec M4 style stocks/braces Lightweight and Rigid Integrated QD Sling Sockets access with stock completely collapsed 7in Length - LOP approximately 8-11.35 inches Compatible with SIG folding mechanisms Allows 2 bolt installation on MRKT folding mech for ultimate strength This is not compatible with firearms that need a buffer tube to function Clamps on any "1913" or "Picatiny" Rail Works with all of our ArmBar Skeleton Stocks and Skeleton Tubes Works with SIG MPX/MCX folding braces/stocks Folds Left or Right Has 2 height adjustments 4140 HT Torque spec: 20 in/lb. Adds approx .5" to stock/brace length Allows your stock/brace to lock in the folded position Attaching a stock to a pistol makes it an SBR and requires NFA approval. You are responsible for knowing and following your local/state/federal laws Package Contents: JMac Customs ST-7 Skeletonized Tube for Compact M4 Stocks for SAM7SF JMac Customs ST-7+SM-SF: ST-7 Skeletonized Tube for Compact M4 Stocks for SAM7SF Black