I have ordered 60 Brccee AC diamond cutters to use with my rotary tools. They do have some downsides as they contain some material that hasn't been handled well on all beats. I don't see this as a problem, but it's worth mentioning. There are 20 different bits, in 3 sets, 60 pieces in total. I like them because they are all quite small and very useful for me when working with small thumbnails. They come in cases that keep the bits in good condition and well organized. I would recommend these hobbyists but not for anything that requires perfect precision as they are not the best bits available. For the price they are good. Thank you for reading my review. I hope my experience is useful to you and please click the button below.