Going wireless is the best decision I ever made for my back and wrist. No more cable drag is a luxury. I picked up the ultron 3 tattoo machine recently, specifically the Max version. The battery life is actually impressive. I usually run it at around 7-8 volts and I can easily get 6 to 7 hours of continuous work out of it. It has a smart energy management system that seems to really stretch the charge. Even if you have a really long session, it charges pretty fast. The balance is great because the center of gravity is low, so it doesn't feel top-heavy like some other battery pens. The display is clear too, shows you exactly what is going on. It is a reliable daily driver for sure.