ABOUT PRODUCTION: 2 Pieces 82mm Laser Welded Granite Core Drill Bits Dry/Wet Diamond Hole Saws for Brick Walls Specification: Diameter 82mm, 5/8-11 Thread, Drill bit total length: 100mm, Diamond Height: 10mm, Hex-Plus Adapter. Quantity: 2 Pieces 82mm Application : Dry/wet drilling for hard granite, marble, engineering stone, concrete, brick wall... Feature: 1. SDS-Plus adapter can to fit to drill or hammer drill easily 2. High quality turbo type segments provide efficient performance and long working life. 3. Centering drill help to position the core drill, it will be easy to do the drilling job. 4. Dry working, Laser welding provide great welding strength and special tube design is helpful for cooling and removing the dust from the hole When the diamond core bit start working, DO NOT use hammer model