Diamond Drill Core Bit Hole Saw Tool for Ceramic Marble Glass Stone(20mm) Description: These drill bits are cutting tools used to remove material to create holes of circular cross-section.There are many sizes for your choice and can create different kinds of holes in many different materials. Attached to a drill which powers them to cut through the workpiece by rotation. Feature: Paint on the body of this bit avoids getting rusty. Opening neat and smooth, no broken edges, no shaking and chip easily. Small incision resistance, drilling stably and will not break the border. Mainly used for drilling ceramic tile, marble, granite, concrete and other hard material. Ideal for drilling the faucet mounting holes in stone counter top. Specifications: Color: Gold Size (optional):  6/8/10/14/16/18/20/22/25/30/35/50mm 0.24/0.31/0.39/0.55/0.63/0.71/0.79/0.87/0.98/1.18/1.37/1.96inch Quantity: 1 Size(mm) 6 8 10 14 16 18 20 22 25 30 35 50 Shank Diameter(mm) 5-11 Weight(g) 11 21 40 35 47 57 63 70 72 96 122 227 Instruction: 1, To prolong its using life, better e with water for cooling and lubrication. 2, The hole drill bit can be used with bench drill, hand electric drill. 3, When you using hand electric drill, start slowly at 45 degree angle and go vertical after you make an initial mark. Package Includes: 1 x Diamond Drill Bit Note: 1. Please allow 1-2mm error due to manual measurement. Thanks for your understanding. 2. There are two types of shank in different diameters and we will send in random. Please take the real one as standard.