Diamond coring motors are used with Vac-U-Rig and Dymorig diamond core rigs to drill holes into reinforced concrete. This 20 Amp 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 in. to 7 in. in diameter.