Joe S If you are asking about the size of the threads, then I apologize, but i do not have the specific info on it. However, It is specific to American Underwater Product Brands, which are Oceanic, AERIS, and Hollis. It will not work on, say, an Aqua Lung BC :) If you need the specific information, then please call the Hollis service department at 800-435-3483.

DAVID B I have Aqualung equipment, some new, some old. I've found common sized valves on them all. Try it, if it dosen't fit you can always return.

Joe S No. The AL specific dump cap is needed for an AL BCD.