These hole saws are a complete waste of money. Through trial and error, I found that they don't cut clean holes and tend to break easily. Even worse, they don't seem to fit properly on my drill. As someone who works in the industrial and scientific field, I need tools that can withstand heavy use and provide accurate results. These certainly don't fit the bill.
used this to drill a hole in my bumper for a trailer connector. I have an old thick steel bumper and it ran fine. My only complaint is that it took so long, almost two weeks.
Shipping took a little longer than most products, so delivery is a little slow. The price difference to the competition is hard to beat. Overall this is a good hole saw that seems to work well.