Ceramic Rectangular Magnets 40 mm x 25 mm x 6 mm Ceramic magnets do not provide the strongest magnetic force handy for scientific experiments, arts & crafts, projects, use in the home for the refrigerator or freezer to hang light weight paper. 1 Magnet Magnet measurements 1.57" x 0.98" x 0.24 Eisco Labs Ceramic Rectangular Magnets 40mm x 25mm x 6mm - 1 Magnet. Ceramic magnets do not provide the strongest magnetic force but these are handy for scientific experiments, arts & crafts, projects, use in the home for the refrigerator or freezer to hang light weight paper.