The aftermarket Smith & Wesson M&P 15-22 Sport barrel nut wrench is made from black hard anodized aluminum. The M&P 15-22 rifle barrel nut wrench tool is needed for easy handguard replacement, tightening and removal of the Smith & Wesson M&P 15-22 .22LR barrel nut. The barrel nut wrench is hollow and designed to slide over the rifle barrel. The tool has machined teeth to interface with the Smith & Wesson® M&P® 15-22 .22LR factory barrel nut. It also has flats on the opposite side for a wrench to tightening or loosening the barrel nut. If you plan on swapping out the factory handguards, you will need this tool to get the factory handguards off. Length 11.0 inches long. Diameter: 1 inch. Vism One year Warranty.