This Stainless Steel Adapter Allows You To Use A Full Size 18Mm Thread O2 Sensor In A 12Mm Original Equipment Bung. Most Import Motorcycles, Atvs Etc. Come With A 12Mm O2 Sensor. This Adapter Allows You To Use One Of Innovates Data Loggers Or Gauges Without The Need Of Welding In A New Bung. This Adapter Allows Mounting The O2 Sensor At A 45 - Degree Angle. The Nut Allows You To Point The Adapter In Any Direction For The Greatest Amount Of Clearance.