Magnetizer Demagnetizer Uses 2 C8 industrial permanent magnets. To magnetize and demagnetize steel screwdriver blades, tweezers and similar tools. Shatterproof Box made from high quality plastic, shock-resistant, green, cadmium free. Assembled in USA Application: To magnetize, lead tool slowly through the (+) opening, to demagnetize guide tool slowly through the (-) opening. Parts under 1" Length or 1/8" Diameter may not demagnetize.