Built for use with ratchets and breakers bars, the TEKTON 4929 Oxygen Sensor Socket makes removing and installing oxygen sensors on vehicles with computer-controlled engines easy. A heat treated, chrome vanadium steel construction ensures that the socket will take on oxygen sensors time and time again. The corrosion-resistant black phosphate finish also adds longevity to the socket. Designed with mechanics in mind, this socket works quickly and efficiently in the tight space around oxygen sensors. The 6-point beveled nose design securely grips oxygen sensor fasteners, preventing damage to the sensor. A side cutout allows you to easily slip the socket onto the sensor, preventing damage to wires. Even in low light, the high-contrast, permanent, laser etched size markings are easy-to-read. The size is also engraved into the chrome vanadium steel on the exterior socket wall.