Bought to try and not modify my manifold with a new 18mm O2 sensor port that is welded in. No problem as the Dynojet Auto Tune AT-200 transducer comes with a Bosch transducer that does not fit this adapter. It's too long. Shame it seems very good quality and well finished in every way and comes with a copper washer, nut to tighten at right angles and all.