Diamond coring motors are used with Vac-U-Rig® and Dymorig diamond core rigs to drill holes into reinforced concrete. This 20 A model features 4.8 peak horsepower with a 600 rpm or 1200 rpm operating speed. The 4005 has a clutch to protect gears and motor against overload. This unit will handle core bits from 3/4 to 7 in Dia.