These units have both hardware and software modifications resolving the 'stuck at low initial amp setting' and 'flashing power light requiring reboot' problems. This revision should allow the use of aluminum stick altogether and better versatility with 1/16" standard stick electrodes on the low end. If you're a prospective buyer, check the serial number before you buy it. If the revisions work, this unit will have no competition on any dedicated 10 amp 120v circuit :p) Its Power Factor of .95, among other slick, slick electrical engineering tricks is MAGIC.