Use with a breaker bar to loosen stubborn oxygen sensors. Tool comes with both 1/2" and 3/8" drive. Attach a 1/2" breaker bar on the end of the tool to initially loosen stuck sensors. Use a 3/8" ratchet on the top for fast removal and installation. Fits oxygen sensor applications with a heat shield. Slotted body allows clearance for wire harnesses. Forged, heat-treated steel with six point design will withstand high torque removal applications.