@ High Quality Diamond Drill Bits with Thrifty, Fast Cutting Surface - Made of high strength nickel plated carbon steel makes these drill bits durable and precise; the tip bit of the head is made of 80 grit diamond coating, which is uniform; it helps a lot in increasing drilling speed and sharper than other regular saws. @ 10 pcs mainly used sizd - Contains the following diameters: 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 25mm, 50mm; Using laser marking, the size will satisfy most of your different needs. @ application - Suitable for use in a drilled hole on glass, marble, tile, jars jars, fiberglass, porcelain and ceramic tile, slate blva0299, light stone granite, etc. It works with all Electric Drill and Impact Drill. @ Nice design - the center of the holes and side holes help to easily remove the waste material; and nickel-plated surface, extend service life, improve surface corrosion resistance @ type of notice - when cutting hard materials, it is important to ensure the bur