Brownells AR-15/M16 Barrel Extension Torque Tool Features The Brownells AR-15/M16 Barrel Extension Torque Tool is inserted into the back of the upper receiver until its teeth lock into the locking lugs of the barrel extension allowing straight-line torque to be applied without twisting or marring the receiver. Torque is delivered through the tool s 1/2 inch square drive working alongside any standard barrel nut wrench or free-float tube wrench and a torque wrench. This method protects the exterior finish of the upper receiver during barrel nut installation a common point of damage when improvised tools are used instead. Precision machining from heavy-duty steel bar stock ensures the tool holds up to repeated use in a home or professional shop. Measuring 9 inches long by 1 inch in diameter this tool is compact enough to store in a range bag or tool chest alongside other AR-15 build essentials. It is designed to fit AR-15 M16 M4 and BRN-4 style barrel extensions covering the large majority of mil-spec upper receiver builds. The kit includes the torque tool itself along with instructions packaged together in a clear PVC container for easy storage. The Brownells AR-15/M16 Barrel Extension Torque Tool is a practical addition to any builder s toolkit for clean accurate barrel nut installation. Brownells AR-15/M16 Barrel Extension Torque Tool Specifications Manufacturer: Brownells Model: AR-15/M16 Barrel Extension Torque Tool Material: Steel Color: Black Oxide Compatible Hosts: AR-15 M16 M4 BRN-4 Length: 9 Diameter: 1 Weight: 1.81 lbs Quantity: 1 Available At: GrabAGun