Come and see our amazing products. USB Design, just place the teacup or coffee cup that needs to be heated on the coaster and then charge it directly to the temperature you want with the USB port. All you have to do is plug it into a USB outlet and it will start to work. You can bring it anywhere you need it to be. it's that convenient. Suitable for Versatile, ceramic cups, glasses, metal cups, etc. Fit for Coffee, tea, milk, and other drinking you want to keep warm. Pls confirm with us about the packing info, stock color and exact production time before placing your order