Fangrui Product Details Premium Quality: This Diamond Drill Bit Set Is Crafted From High-speed Steel And Designed With A Thick Diamond Coating. This Tough Composition Makes The Drill Bits To And Enhances Durability. Each Bit Stays And Can Easily Drill Multiple Holes, Offering Extended Utility And Precision. Bit Dimensions: Each Hole Saw Bit In The Set Comes With An Optimal Dimension - 0.24inch/6mm Hole Diameter, Up To 30 Mm Drilling Depth, 51 Mm Total Length, And 5.5mm Shank Diameter. These Details Maximize The Utility Of Each Bit And Ensures The Maximum Number Of Revolutions: 800/minute. Advanced Design: These Drill Bits Are Designed With Clearance Holes To Improve Efficiency. The Side Hole Lets Cooling Water In, Reducing The Risk Of Overheating, While Also Allowing Chip Debris To Escape, Making Your Drilling Process Smoother And More Comfortable. Compatibility And Variety: This Bit Set Is Versatile, For Drilling Different Materials. You Can Use Them On Glass, Tiles, Porcelain Stoneware And, Slabs Among Others. Our Dri