Size: Totally 5pcs/set: Diameter 6mm 1/4",Total length 65mm; Diamond height 8mm; Diamond Grit #50/60; Hex shank 6.35mm; with 2pcs 1/4"(6mm) Carbide Tip Drill Bits. Application: Dry or Wet drilling Ceramic Porcelain Tile Marble Granite Mirror Plant Pots Wood, etc. Cooling Wax: The inside of drill bits are filled with cooling wax, help heat dissipation and chip evacuation. Dry drilling without water, very convenient. Vacuum Brazed Technology: Vacuum Brazed Technology and high quality diamond grains provides fast and smooth drilling, longer working life. Diamond material upgraded, can drill 10-15 more holes than ordinary drill bits. Recommended Machine: Diamond dry drill bits suitables for Corded Drill, Cordless Drill, Benchtop Drill. Recommended speed: 2000-5000RPM; Faster the RPM, Longer the drill bit's Working Life. When use Angle Grinder, please install angle grinder drill chuck.