The FAST? Wide-Band Air/Fuel Gauge Kit combines an economical and extremely accurate 2 1/16" gauge, Bosch wide-band oxygen sensor and standalone sensor control unit that mounts quickly and easily in the interior of any vehicle. Back lit for easy night viewing and wired so it is powered up whenever the engine is running, this kit is not only for serious power tuning but also ideal for monitoring the overall fuel tune of the engine when daily driving or making passes at the track. Kit includes gauge, module, harness, sensor and bung.