Purchased in addition to a set of these bits I bought six years ago. I just replaced a 2 1/2" drill bit after drilling countless holes in various metals.
Pros
Package dimensions: 9.144cm (L) x 13.97cm (W) x 2.286cm (H)
I convert cars to natural gas and have to do a lot of custom work including cutting holes in truck/van bodies and side panels. I've blown a lot of hole saws from the big stores but they didn't last very long. When used properly (low speed, sufficient pressure), this cutter has survived 15 magazine bits. The quality more than made up for the extra price. Yes, you have to cut the mandrel separately, but of course it can be reused.