If you're handy these little guys are great! They cost about $6.50 to make and @ about 900mah on the battery last even longer than an ego.
MadVapes e-Cig 'How To' Tutorials • View topic - 2xAA 3.7 Volt Box Mod
MadVapes e-Cig 'How To' Tutorials • View topic - 2xAA 3.7 Volt Box Mod