I am very impressed by the Kr8 auto
batteries, especially those sold by
Bloog and
Smokeless Image. The latter is less expensive: only the 220 mAh short 65mm ones right now, but I prefer these anyway for hands-free
vaping.
Stick an inexpensive 808/901batt-to-510 adapter (e.g., $1 from
Good Prophets) on it and you can vape the 510 atty/carto/tank of your choice. As long as it is 2.0Ω or greater; LR attys/cartos should never be used on batts less than 450 mAh.
BTW, the Bloog and Smokeless Image Kr8 cartomizers (no adapter required) are excellent. I'm partial to the Bloog ones over the current ones from Smokeless Image, but I understand that those are going to be filled with the same juice that Bloog uses ... and many vapers (e.g.,
SteelJan) like them just the way they are.
There also is a wonderful much higher mAh automatic battery, but it is considerably larger (and, therefore, would be more of a strain vaping it hands-free): the
Echo. I reviewed it
here. It also is Kr8-based, but the same adapter will do the same trick ... and LR attys/cartos
are permitted. The 650 mAh version (e.g., as sold by
Sterling Vapor) is shorter and might work hanging from your mouth.