AS TOOL CENTER 2pcs Diamond Drill Bits 18mm Serrated Hollow Core Hole circle from glass, tiles, marble, granite, ceramic 5PCS

Description Size - Drilling diameter: 18mm / 0.71"; drilling depth: 30mm / 1.18"; round shank diameter: 8mm / 0.31"; total length: 55mm / 2.17". Material - Using electroplated diamond (50-60 grits), the opener creates precise, smooth cuts with no broken edges. Nickel plating improves hardness, wear resistance, corrosion resistance, and greatly extends the drill bit life.. Features - The serrated drill bit increases the sharpness and opening speed. Sharper and more durable than ordinary electroplated drill bits, especially suitable for thick glass openings. (10mm thick glass generally has about 300 openings.).