I just got the Knight Rider Mini VV Mod from ecigcharleston.com. I've been vaping 3.7V devices for quite a while and then I got a 5v passthrough. I've always been curious about being able to set my own voltage to deal with different cartos/tanks/etc. and different flavors. Well I must say that I found what I was looking for in this mod. It is basically a "lava tube" style VV mod, pretty much the exact same thing. It hits like a champ from 3-6V, and if you have an atty on that can't take whatever voltage you have it set at, it automatically drops the voltage to meet the ohms of the atty/carto/tank. I'm using the 4 ohm cartos that came with it, as well as a 4.5 ohm atty that I bought extra. They sent me a killer sample of "Fireball" juice that ROCKS at around 5.3V in the atty. Great kit, great price, free juice, I love it!!