Im sure its just a op amp, with a probably a smoothing cap due to the egos pwm 3.2v. the "button" on the booster is infact just a dial for the varistor all the way clockwise is 3.2V and all the way counter clockwise is 4.7v with the in betweens being in between. the extra voltage would come at the expense of extra current, so therefore lower battery life.probably akin to LR atties like 3.2v and 1.5ohms is 2.1amps, so about 6.8watts of power.. I dont think you wanna stick a lr at 1.5ohms and 4.7v cause that would give a unregulated 3.1 amps and i dont think the ego battery would like that much. even though i have been using a 1.8-1.9 ohm atty, in reality its probably not the greatest on the battery. any way that is all way off the mark, this thing is pimp, and im sure you could use this on any 3.7v battery with varying levels of success depending on the ability of the voltage source you use.