This is a fantastic set. I live in a rural area and finding a job, including electrician, is almost impossible. I used this to make some holes in the generator backup switch. 2" is the maximum size with a 2.5" bit. These bites are individually very expensive. This set has already paid for itself. Easily cuts through panels. They will probably withstand more than 50 cuts of ordinary sheet steel without a problem. Heavy stuff, well, it probably won't last long.