Black anodized finish aluminum construction M&P 15-22 barrel nut wrench. For handguard replacement, tightening and removal of Smith & Wesson M&P 15-22 .22LR barrel nut. Wrench is hollow and designed to slide over the barrel. Tool has machined teeth to interface with the Smith & Wesson® M&P® 15-22 .22LR factory barrel nut. 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 hand guards off. Length 11.0 inches long. Diameter: 1 inch. Ncstar One year Warranty