Connection ½ BSP, For use on diamond and/or percussion drilling machines. Drills the hardest materials which were previously incapable of being drilled dry. Dust-free if you require. PC850 drills hard materials which previously could not be drilled dry. Engineered in the UK for the hardest of materials. Drills in 2 ½ minutes what traditionally took more than 14 minutes. Lowest costs per hole because the PC850 lasts so long. A must have for professional plumbing, heating, electrical engineers.