These are used when installing an HHO system or a test pipe. They are also used to adjust the air-fuel mixture for improved fuel efficiency. Installation is simple: unscrew the existing O2 sensor from the exhaust, thread the sensor into the extender, then install the assembled unit back into the exhaust. The extender features a 7/8-inch hex head—matching the size of most O2 sensors—for easier installation compared to straight-sided extenders. It fits most sensors with a 1/2-inch diameter tip. Dimensions: 1.50 inches in length and 1.253 inches overall length, with an internal diameter of 0.5175 inches. For additional clearance, units can be stacked. Tapered design eliminates the need for a washer. Color: Silver Material: Iron Model: 1.5 Universal fit for any 18mm threaded O2 sensor Straight bolt-on installation—no modifications required Easy to install Package Contents: 1 x oxygen sensor extender Note: Color may vary slightly due to lighting and screen settings. Measurement tolerance: ±1–3 mm.