Grabber hex head framing screws attaches heavy gauge 20-12 ga metal to metal. Designed for use in heavy gauge metal to metal applications where high torque is required. Includes a Nutsetter inside each box of screws. Use a standard screw gun with a depth-sensitive nose piece. Suggested screw gun specification for optimal performance '“ 4 amps minimum and RPM range of 0 to 2,500.