7PC O2 Oxygen Sensor Socket Thread Chaser O2 Sensor Wrench Removal Tool. 1pc 1/2″ Drive x 7/8″or 22mm (6 point) long oxygen sensor wrench socket with slot. Standard 6 point with low profile and 8mm x 64mm side cutout design to enable you remove oxygen sensors with the wiring harness still attached, and the socket is offset and compact which allows extra leverage even in hard to reach spots.