See I dont know if its my multimeter or my booster. But I droped my booster and noticed I was getting a lot more vapor afterwards. So when I got home I put a meter on it and it read 6.64v
. and that is at any position on the dial. I took the booster off and checked just the batterey and it read 3.7v. So my booster is mega boosting. The good part is that its not burning the wick or liquid so its not tasting bad. I will not be sending it back cause I really dont have a problem with this but I will be getting an other one on the christmas yo yo if they are in stock.