I'm shopping around for a new battery(ies) for my K200 (side note, I LOVE that thing) and I can't find any that seem... Good to me. I want something that lasts long, gives a consistent charge, and won't get fouled up by any awry charging habits. My battery now is around 64mm long with about a 16mm diameter, so I can probably fit something a little bigger in my mod. But I need brands, models, capacities, anything helps. UPDATE: Just learned that 18650 is the dimension of the battery... No need to point that out.