The black valve could also be on the wrong way around. Remove it from the tubular, remove the valve core below ( if there is one) and insert the other end. Then screw the valve core into the larger diameter end of the extender.
Perhaps, I’ll probably just return it to the eBay seller though. No flats on the valve core so any removal would likely mar the threads.
@dbr started
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The black valve could also be on the wrong way around. Remove it from the tubular, remove the valve core below ( if there is one) and insert the other end. Then screw the valve core into the larger diameter end of the extender.