Eclipse Magnetics M19088NR Alnico Rectangular Bar Magnet, Maximum Pull of 1.7 lb, 4" Length x 3/8" Width 3/16" Height Rectangular Bar magnets made from Alnico Grade 5 material, unpainted in color gray and have a maximum temperature of 550 degrees C Length tolerance is +/- 1/8", width & thickness tolerances are +/- 0.016" 4-inch length, 3/8-inch width, 3/16-inch thickness Maximum pull of 1.7 pounds