Custom Made 40mm x 40mm Magnets Diamond If you like your promotional magnets to sparkle, then our custom made 40mm x 40mm (1-1/2") diamond magnets will be just the thing. These custom made magnets are constructed from tough metal components that will last for years, and the strong magnet is more than capable of holding bills, brochures and menus to any fridge, filing cabinet or locker. Simply add your artwork or promotional message and we’ll do the rest. Our 40mm diamond magnets make ideal take-aways for trade shows, conferences or even the local coffee shop. Pop a magnet in a customer’s bag and let them take your message home with them.