I have to tell you that I have one of these "magic" cartridges 3.5mm in a brass Vivace and I can get this to run slower than I will ever need to go. I like my color packers to run at speeds that just about defy the range a coil machine can reach so this thing is a dream to me. I solid filled a big coi fish on a friends arm at the Mesa, AZ show in about 4 hours. That is fast for a guy that is only tattooing a dozen or so times a year right now. It felt a little strange to be seeing 12v on the Critical power supply but Ray told me that equates to his standard motor running at just below 5V and we all know that they do not like to do that with any real torque. Kudos to Ray on the new cartridge and Thanks for letting me play with it!!!