Forney 58559 300-Amp Ground Clamp Industrial Pro Magswitch Magswitch ground clamps utilize advanced switchable magnetic technology to allow welders to quickly set up Easily attaches to flat or round stock with a quick and easy connect/disconnect Simply place it on the work surface and-1/2 turn of the knob turns the magnet completely on or off for easy cleanup No need to tack on ground tabs or waste time searching for a ground location No batteries or electricity required