Magnet Counterparts. Basic plated steel discs, designed to complement the RS Energise to Release and Energise to Hold magnets. ; 739-3264 739-3264 = 25mm Dia ; 739-3211 739-3211 = 30mm Dia ; 739-3255 739-3255 = 40mm Dia ; 739-3251 739-3251 = 50mm Dia ; 739-3217 739-3217 = 65mm Dia ; 739-3214 739-3214 = 80mm Dia