The 2" Tri Clamp Cap has a 1" NPS thread and is compatible with all tri-clamp and tri-clover fittings. This cap has a hole in the center that is compatible with 1" NPS heating element connections. Tri clover caps can also be drilled and welded to make other fittings. Having several extra tri clover caps around is always a good idea. These end caps are manufactured from 304 food grade stainless steel.