I'm confused about these batteries. When I first ordered a few weeks ago I ordered the standard kit (not realizing that the ultimate kit had a charging case) so I've got to get a charging case, I suppose. But the batteries - how much longer is an extra long battery? I assume what came in my kit was the short auto batteries ?- and bless them, they sent me a manual to try! It seems a little more slim (which I like) - and works better. But now there are new extra longs - I love the single logo batts - but what is the difference in the ex long? Is it the length of charge time? Are they more slim also? I smoked Eve - which are very long - so this manual that is slim seems to be more like what I smoke - I ordered again for extra flavors to try - am seeming to love the 555 most of all, but am trying more to be sure I'm at a happy place because I feel like this is truly going to work for me. I love it. I was scared to try refilling - but I did one cart last night and I didn't make a mess, it wasn't horrible, and the flavor is good! Thanks V4L! I told a friend about it today - am anxious to see him again to pass a card along to him.