A AND S Tools Drilling Diameter: 20mm/0.78"; Drilling Depth: 25mm/0.98"; Total Length: 50mm/1.96". ?Quality Material?- Diamond coating maximizes performance and retains a sharper cutting edge than traditional carbide or bimetal hole saws.Side holes allow for easy slug removal after drilling. ?Nickel Plated?- Nickel plating on these bits maximizes your tools life with great resistance to corrosion.Well made, sharp, hard, lasting. ?Application?- Cutting accurate holes on glass, ceramics, porcelain, porcelain tile etc.. Not suitable for drilling tempered glass, plastic and wood. ?Warm Reminder?- Please use at low drill speeds and drill pressure. Always work with coolant (water) when drilling.