This weld-in steel bung allows you to change or move your petcock (fuel valve) location to wherever you desire. Also very useful for oil tank fittings. Very handy fabricator part for custom motorcycles, choppers and race vehicles of all types. 3/8" NPT thread, steel. Sold In Pairs. Made in the USA. National Pipe Thread (NPT) is a U.S. standard for tapered threads used on threaded pipes and fittings. The taper on NPT threads allows them to form a seal when tightened. These are NOT used for mounting bungs as standard bolts do not fit into the tapered NPT threads.