Ace Race Parts 74004 M18 x 1.5 O2 Sensor Bung - Heat Sink Style - 6AL4V Grade 5 TitaniumAce Race Parts 74004 M18 x 1. 5 O2 Sensor Bung Heat Sink Style 6AL4V Grade 5 Titanium EXTEND THE LIFE OF your WIDEBAND O2 SENSOR! Ace Race Parts O2 Sensor Heat Sink Bungs are precision machined using solid 6AL 4V Grade 5 Titanium bar stock and work with all standard O2 Sensors that use a M18 x 1. 5 thread. The extended finned design of Ace Race Parts Heat Sink style O2 Sensor Bung Clamps helps keep the sensor body cool, thereby extending the life of