I just sold one on the classifieds. I mainly use dual coil cartos and it just couldn't seem to handle them. It would adjust from 3 to 6 volts. But checking under load with the DC's, voltage turned all the way up, meter was only showing 3.2 volts. WillyB reminded me that it was probably the 2 amp cutoff kicking in. So I decided to let it go. But as far as single coil atties and cartos, I'm not sure how it will do. You will have to experiment with different resistances to find the sweet spot and keep within range right below the cutoff point. Somebody with more experience in this area would probably be able to answer better