Friend I work with found these in his father's old vietnam helmet bag. Not much I can tell you that isnt obvious in the pictures. The aquadive you can feel something moving if you shake the watch back and forth, but only in 2 directions. From my research this shouldnt be a bumper though. Any info I can get, exact models, the movements in them, rarity, difficulty/cost to restore to running/wearable condition would be much appreciated.