1. USB plug-in interface for sustainable heating safe to use.
2. Connect the beverage warmer to your computer or 5V USB port. Keep your cup on the usb silicone coaster.
3. The berverage warmer just help to provide insulation can not be used for heating.
4. Please disconnet the usb port when you do not use the beverage warmer.
5. Stainless steel cups ceramic cup bottle glass can be safely put up.