Keep you warm on cold days-the coffee cup heater is easy to carry. Drink your favorite morning cup of hot coffee at your desk at work, or keep a hot cup of hot tea while relaxing on the sofa. Ideal gift for coffee/tea lovers. Beverage thermostat---The teacup heater has a built-in thermostat, which can keep your beverage (tea, coffee, milk tea, etc.) at the perfect temperature from the first sip to the last drop (50-80). Please note that the desktop USB heating coaster can only be used for heat preservation and cannot boil water. Safe and durable---USB coffee cup heater is made of high-quality walnut wood and metal materials, which is evenly heated, safe and durable to use, with natural walnut wood grain and smooth hand feeling. USB Port Powered --- Any device with an output 5V USB port, such as computers, desktops, laptops, tablets, mobile power supplies, etc. The compact design keeps the drink warm throughout the day. It is an excellent gift for lovers. On Valentine's Day, Thanksgiving and Christmas, dad, mom, wife, husband and all your loved ones. Suitable for most mugs --- The coffee cup heater is suitable for most mugs, such as glass cups, stainless steel cups, ceramic cups, etc. For better results, we recommend using a flat-bottomed glass or stainless steel cup. Putting a lid on the cup will also help retain heat.