Package Content : 1 x Diamond Drill Hole Saw Diameter: 16 mm / 5/8 Inch Shank Bit Size: 20 x 7mm (L*D);Total Length: 50mm; Material: Metal, Diamond Particles Coated This bit can be used on glass, marble, granite, fiberglass, ceramic and porcelain tile From the Manufacturer: 1. The end of this drill bit is grooved, so the diamond coating has better adhesion for longer life 2. The side hole allows water to lubricate inside of the drill bit to insure an smooth and perfect hole 3. This bit can be used on glass, marble, granite, fiberglass, ceramic and porcelain tile