Advertising in cars or in any other vehicle using these Outdoor & Car Magnets 30 Mil Round Corners is a very good idea to attract people towards your brand. In order to gain maximum exposure you should try different tactics with these custom rectangle magnets. If it is for cars them small and larger text/images will be best for visibility, whereas if these custom magnets are for a door or any outdoor machines then a little more detailed design and matter will work.