Description Good Percompatible withmance and long lifeExcellent compatible with making clean and accurate hole on glass and tileWorks better with a electric drill(Excluding in the item)These Diamond Bits are Capable of Drilling into Extremely Hard Materials Such as Stone and Glass.Use a Low Speed Setting and Proper Cooling,Such as Water,to Superior Percompatible withmance-Cut Holes in Marble,Slate,Glass,Tile,Stone,etc.Great compatible with Home,Hobby,Craft,Construction,etc. Color:silver material:metal Size:20mm Quantity: 2 pieces Package Contents: 2 x diamond hole sawOnly the above package content, other products are not included. Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is + /- 1-3cm.