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.