There were several aboard subs, one for each battery well. Mostly hygrometers and related gear. We have several with most of the gear. But the rubber bulbs have turned to brittle gunk. My contacts tell me they were stowed down in the battery wells, so to have one on display on the tour route would be inaccurate. That is nice to know. Now LING should have one in each of her fully intact wells.. the rest of us can only grin with green envy.