If you are planning to replace your own O2 sensor, you're well on your way to saving some serious money on car repairs. Before you start, you should know about this special socket you need to get the old sensor out and the new one safely installed. This applies only if your O2 sensor is a threaded type, not a weld in type. If your oxygen sensor screws in, this socket is a must. Check it out.
Without this tool you can't remove or install an oxygen sensor with a ratchet wrench. This makes the job much harder. Your O2 sensor has wiring coming out of the end of the unit. With a regular socket there's no place for this wiring to go, and the socket won't fit over. This slotted socket lets the wiring slide safely out of the way so you can get cranking.