Use with a Breaker Bar to Loosen Stubborn Oxygen Sensors. Tool comes with both 1/2" and 3/8" drive. Attach a 1/2" breakerbar on the end of the tool to initially loosen stuck sensors. Usea 3/8" ratchet on the top for fast removal and installation. Fitsoxygen 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.