So you do not mean slim
batteries.
Ego-T
batteries only because 5-clicks to disable them (good for pocketing)
or for more voltage (more heat)
Riva 510 at Liberty-Flights only. I know the KITS are the new model from the correct manufacturer - they are a 3.7v model. I do not know if the loose batteries all are but the SE batteries are 3.7v
Experimental (new) - the 3-stage "Ego" (clone) batteries at Gotvapes - 5 clicks to switch from 3.2 to 3.7 to 4.2 volts. Certainly feels decent right off the charger. But there is no track record on reliability yet.
or get a mod like E-power (if I am correct about it being 510 threaded) or other 510-threaded mod.
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If you DO mean slim batteries, then the best 510-threaded slim battery is a Joye brand 510 mega xl MANUAL battery. These are 280mah and 128mm long with a Boge carto.
If you mean any threading with an adapter, then KR808D-1 Smokeless Image Volt XL manual XL length for (I think) 400mah?? The Vapor4Life verison is mostly sealed and a bit less mah with a standard size button. You would need an 808 to 510 adapter. Tiny button but a fully sealed threaded end. This would be very very long - probably over 140mm. KR808D-1 batteries alsoare 3.7v, more voltage than 510 or Ego. You should not use LR cartos on any of these. LR cartos are for the fat batteries and mods listed above.