Nắp chụp và nút bịt cổng BCD Inflator & Dump Valve

This cap and plug fit SeaQuest, US Divers, Aqualung and other BCD inflator and port as well as the quick dump valve opening on the back.  The thread size is imperial 2 1/8-12.

They are useful to protect threads if one removes the inflator and/or dump valve assembly for travel (I pack my inflator with regulators, separate from other heavy items to protect from damage if the bags are handled roughly - yes, OCD.), and for bcd deep cleaning after trips.

There are a number of similar models on printables for scubapro, but none of them fit my gear, so it is a safe bet that the converse is also true.