I will try to answer. The one's on Ebay look to be well used and nobody will guarantee them to not leak like mine. Add that to their asking prices and they don't look so good. And no, you're not confused. The last question is a hard one. I can pump it up to at least 75 lbs and then with motor off I listen with my ear very close to cylinder and I can hear nothing at all. BUT, it drops to less than 10 lbs within a minute or less.