Personalized teacher coaster! Great appreciation gift for the prefect teacher. The coaster can be personalized with a name and the name is sealed in epoxy resin for a smooth finish. Resin is not crystal clear like glass or acrylic micro air bubbles do occur. I do try to get as many bubbles out as possible. The thickness is 0.16in, the outer diameter is 3.5in, the inner diameter is 3.25in, the height is 0.39in.