This bung is designed for adding O2 sensors to primary header pipes - a MUST for proper tuning of 2 cylinder odd fire engines.

The bung has an extended length that places the tip of the sensor flush with the inside of the pipe so that it doesn't restrict flow.

It is machined from 304 Stainless Steel, with standard M18 x 1.5 threads.

It is coped for a 1.5" tube, but works well on 1.25 - 1.625" tubes.