Car Magnets Glossy 30 mil heavy duty magnets with a variety of uses. Best suited for car door signage. It is highly recommended testing a sample of our car door magnet on the specific vehicle you will be using the car door magnets with, as some cars have aluminum doors and magnets will not stick. These magnets can also serve as temporary signage for construction sites or other quickly changing work environments. Printed with the same UV ink technology as our outdoor banners and coroplast yard signs for long lasting outdoor use. Not intended for small text size or borders.