The polymer mugs are specially offered by SUN-FLY. They are made out of sublimatable polymer material that does not need sublimation coating - images can be dye-sublimation printed directly through the surface of the mug. Resulting longer lasting of printed images. Compared to ceramic material, the polymer mugs are virtually unbreakable, and have either matte or gloss surface finishing. All polymer mugs are FDA approved and RoHS compliance.