First setting is a true 2.0 volts since its based on the carts actual resistance, with .1 volt increments up to 4.2v! It works just as good as the Joyetech eCig mod I've used for a few years specifically for low power hits - this Yocan UNI Pro is fantastic for thick/terpy oils. I never used the original UNI, but this one is definitely better than all their other current batteries for true flavor chasers. The low settings are perfect on this, to give you an idea I tend to hit my Groote/Wit on the preheat setting, so this one can fire super low, very efficient too. Not the smallest pen battery in the world but for high quality carts like I know you like it's legit. It's pretty light too, I think my little Groote actually weighs more, I'll check when I get home.