Yes, they are aluminum wires in the Lincoln and it is a tapped current control and 20% duty cycle. Actually, according to Lincoln, they have a 20% duty cycle on ALL settings except the 75 amp setting. This setting used to have a circle around it and was used with a carbon arc torch or a pipe thawing unit, both of which are no longer available. Having a 50 year old Lincoln SA200 Red Face is a good thing to have. Having a Lincoln AC 225 or AC 225/DC 125 that is 50 year old technology... not so much. Nothing wrong if you already have one but to buy a brand new one when there are so much better and less expensive machines on the market doesn't make sense to me. I'm 99.9% certain Shield Arc only mentioned the AC/DC version because DC is much easier to weld with than AC. If you are dead set on having a Lincoln welder, look for a used Idealarc 250 AC/DC. Then you will have an excellent machine. Lincoln has a lot of components made in Mexico, Italy and I'm sure other countries as well. If you're a beginner welder, having the best machine you can afford will drastically reduce the learning curve and frustration level. This is only my opinion but if you limit your choices when looking at a welding machine, you're limiting your chances of getting good at it. Sorry if I seem harsh. That's not my intent. I don't want to see someone spend their hard earned money on something they'll want to replace after they try a better machine.