How to create a permanent source of marketing through these Magnets - Outdoor & Car Magnets 30 Mil Square Corners? It is easy, just imprint your brand logo and contact details onto these custom rectangle magnets and place them in your regular customer's cars. Also click a photo of the car and the customer as part of the campaign and paste it in your social media profiles, just to create some reputation. These magnets are waterproof, UV safe and also fade resistant.