Large Demagnetizer Demagnetizes or magnetizes parts, tools and meters. To demagnetize, hold object in the center of the opening with button depressed for 3 or 4 seconds. Slowly withdraw object in a straight line and release button. To magnetize, hold the part or tool against the inside of the opening and press the button for 4 or 5 seconds and release. Opening is even large enough to accommodate cassette tapes for quick erasure. Opening measures 3" x 1-1/2".