Its not an arc welder, its flux core wire feed, aka gasless mig. The HF one may be able to add gas if desired (some do).

I dont have the HF one, but I have a Speedway 115v 125amp flux core. Works good for small jobs, great if you are just starting out and need the practice. It will do up to 1/4" or so once you get good with it. I use it to tack things together, but I wouldnt stake my life on it though.