Aiskaer 15 pcs Diamond Hole Saw Drill Bit Set - Diamond Hole SAW Drill BIT FOR Ceramic, Porcelain Tiles, Glass, Marble, Granite,Diameter 4mm to 40mm (15PCS) 1.Made of high-strength steel and high-quality corundum powder, and fine workmanship; durable, high precision machining, smooth appearance, heavy quality. 2.Diamond Hole Saw bits are versatile drill bits that allow you to cleanly cut glass, ceramics, porcelain, ceramic tile, porcelain tile, limestone, slate, marble, granite, light stone and fiberglass.This diamond coated core drill bit removes a complete circle from glass, tiles, marble, granite. 3.Easy to use, high quality,good performance, long life - Excellent for making clean and accurate hole.All the bits are processed for a smooth and exact finish. 4. Attention: Please keep the speed in 800-1000 per minute, keep adding water to keep the drill cool, strictly prohibit from dry drilling! 5.Size(Diameter):4mm,6mm,8mm,10mm,12mm,14mm,16mm,18mm,20mm,22mm,26mm,28mm,30mm,32mm,40mm