If battery capacity isn't a big issue and small size is your priority then a pod mod with a 510 adaptor comes into the mix. Very small in comparison to mods yet @Room Fogger will back me up they work great with the adaptor and actually feel a much more solid device, perfect for MTL set-up. I have 510 adaptors for RPM, Vinci and Boost and they all only costed £5 and work great make my single 18650 devices seem massive!ah man f$#$#$$#k, and when was this, I should of waited,