3" Wet Diamond Polishing Drum Wheels are used to polish inside radius such as undermount sink holes. They are much easier than diamond polishing pads to use when polishing inside radius. Wet polishing will generally result in better shine and also the tools will last longer. With 5/8-11 thread, the wet diamond polishing drums can fit on most polishers and variable speed grinders. There are 8 different grits including 50 grit, 100, 200, 400, 800, 1500, 3000 grit and white buff.