The Brownells AR-15/M16/M4 buttstock tool is a compact and versatile instrument, specifically engineered to integrate multiple tools into a single unit.

• A spanner wrench designed to fit the receiver extension castle nut on M4-style collapsible buttstocks, featuring interchangeable pins to accommodate nuts with both older round and newer square teeth
• For fixed rifle buttstocks, a screwdriver blade is used to remove the buttplate screws and a wrench is required for the nut on the receiver extension tube
• The tool features a 1/2 inches square opening compatible with a torque wrench, as well as a hole designed for hanging on a pegboard
• Conveniently fits into a range bag or pocket for use outside the workshop