Size-----Diameter 5/16''(8mm); Total length 130mm; Diamond height 100mm; Diamond Grit #40/45; 5/8''-11 Thread Application-----Very useful for mortar raking and brick removal, removing old mortar prior to repointing or removing blown, damaged bricks or natural stone Vacuum Brazing Technology-----High-quality diamond raw materials and vacuum brazing technology provides faster removal work and longer service life Best Choice-----It is better suited and easier to use on intricate and delicate work, particularly vertical joints and natural stone jobs Recommended Machine-----5/8"-11 Thread Angle Grinder (Attention: It doesn't make holes. This is not a core bit for drilling. But it can be used for mortar gap cleaning and grinding). Dry or Wet use. Recommended speed 6000RPM, maximum speed 11000RPM. If you want to use electric drill or other machine, you can use SDS or other Adapter