Magnetic Material Sheet 12 x 20-inch (.030 in. thick) Black Thin & Flexible for Magnetizing Bumper Sticker Flexible magnetic material is black on both sides. 12 x 20 x .030 inch Clings to any steel surface Very thin., .75 mm, about 1/2 as thick as a penny. Please purchase from Lifeweaver LLC to assure item is not an inferior counterfeit.