Review on 60-Piece Brass Wire Brush Cup Wheels Polishing Kit for Die Grinder Rotary Tools, 3MM Mandrel, Polishing Attachment, Cleaning Brush - PHYHOO Accessories by Art Porras

I found these brushes shed bristles and hold not long at all when used in a Dremel tool. This seems to have more to do with the speed of the tool than the actual durability of the bristles. I only ran the Dremel at medium speed (probably around 15,000 RPM) but found stubble all over the work area and the brush wore out within minutes with light pressure on the copper plate. I threw one in my cordless drill and ran it at around 1000rpm and didn't have this problem. Worked very well and lasted much longer at lower speed. The description says they can run up to 25,000rpm (almost full speed on a dremel) but that's not my experience.