Magpul Armorer’s Wrench for AR15/M4 Tool for USGI barrel nuts, receiver extensions and castle nuts The Magpul Armorer’s Wrench – AR15/M4 is an American-made, solid steel tool with grip-enhancing phosphate finish that engages both stock and pin-style barrel nuts. Fits standard sized flash hiders. Installs and removes rifle receiver extensions and carbine castle nuts, and has extended teeth for use with ASAP plates. Includes two hammer faces. The Magpul Armorer’s Wrench works with a 1/2″ torque wrench, and relevant torque specifications are included on the tool for quick reference. Convenient Bottle Opener for refreshments after the build is complete (fits both Metric and SAE bottle caps). Made in the USA. American-made with US steel Heat-treated steel construction with manganese phosphate finish USGI torque spec references Bottle opener