ZFE Diamond Coated Grinder Head Lapidary Burr Drill Set For Dremel Rotary tools Diamond Burr Bit Sets--50 pieces kit; there are many shapes, such as sphere, cylinder, round head cylinder, needle, flat plate, etc. Different Shape--each burr is a different size and shape, resulting in an assortment that works for almost every need. Use to--carve hard materials,ceramic, tile, Metalworking, glass and stone, and the different shapes to carve realistic paw prints. When using it, you have to be careful and not use on really heavy work or they get hot and let go of their diamond material. Material--diamond burr sets is made of diamond; the shank diameter of the bits is 1/8" (3.17mm). Above all for your reference welcome to buy