I tried it at the default setting first which was 4volts. Not a big difference from a freshly charged 3.7volt. All my other devices are 3.7volts, but when the battery is partially used, the flavour decreases...bigtime. I constantly charge non depleted batteries because of this. I tried one of my fav juices on the ProVari at 4.7 and it is so much better than at 3.7. Another of my juices at 4.7 is not as good as at 4.3. I haven't tried the 6volt yet...I have to take a break, or I'll overload. I'm loving the ability to change the voltage depending on what I'm
vaping...and I won't be getting loss of power with a partially used battery. I'm very very impressed!