The Eleaf iPower 80w has a massive 5000mAh internal battery that should keep you going all day even at full power. It has the usual set of power and temperature control modes; Wattage, Temp Ni/Ti/SS, TCR and ByPass. It’s charged by micro USB and is also firmware upgradeable, which is always a bonus.
It’s hard to believe a mod this size is even possible, but Vaporesso have gone and done it. Up to 40 watts output, a 1400mAh internal battery and a 0.5″ OLED screen. This is the stealthiest mod we have ever seen, infact most tanks are bigger than this little guy O_o