USB thermos cup coaster is a good choice for you to recommend to customers as promotional gifts. USB Cable Heating Coaster is made of PVC. The Mug Warmer Coaster is powered by the USB cable connecting with the computer or adapters. It well deals with the problem of coffee cooling quickly in the cold winter, you can warm your drinks whenever and wherever. The convenient cord length for use almost anywhere, great for home use, office use and anywhere has USB port. Custom logo are welcomed!