Sublimation printing ,also called heat transer printing or thermal transfer printing, is a more advanced technology in printing industry. These sublimation printing keychains are to print the photos on the mdf board and make them into keychains.Expect for photos of your family, you can print the company logo, advertising slogan,anime images or any other images you want to print. It's a good choice for souvenir gifts, ornament gifts, promotional gifts,etc..