Innovate Motorsports HBX-1 (Heat-Sink Bung Extender) - 3729KEY FEATURES HBX 1 Heat Sink Bung Extender The Bosch LSU4. 2 and LSU4. 9 wide band O2 sensors (shipped standard with Innovate Motorsport products) are rated to operate at an exhaust gas temperature of < 1,700 F (930 C), and a sensor housing temperature of < 1,058 F (570 C) measured at the hex, for maximum accuracy and control. When either of these operating temperature ranges is exceeded, the sensor can no longer be accurately controlled. Further,