THERMOSTATIC COASTER: made of high quality walnut and metal material, heats evenly, safe to use and durable. Keeps your coffee, tea or other hot drinks at 55°C without worrying about high temperatures and high oxidation, safe to use. Ideal for home and office use, allowing you to enjoy a warm and delicious coffee or drink in cold weather. LEADING THE WAY TO HEALTHY LIVING: The coffee mug warmer meets the needs of the modern home or office, allowing your coffee, milk or other hot drinks to be kept at the right temperature, all day long, even in cold weather, while protecting your gastrointestinal health. EASY TO USE: The thermal coaster is lightweight, small and portable, and can be powered by any device with a 5V USB output port, such as your computer, desktop, laptop, tablet, mobile power, etc. It can be used anywhere. THE IDEAL GIFT FOR COFFEE/TEA LOVERS: the coffee cup warmer is convenient and portable. You can still feel the temperature of your favourite cup of coffee on your desk in the morning while you work, or you will always have a hot cup of tea at hand when you relax on the sofa. If you're still worried about what to get as a gift, then this stylish coaster is sure to be one of your choices. SUITABLE FOR MOST MUGS: the heated coaster is suitable for most mugs such as glass, baby bottles, stainless steel mugs, ceramic mugs etc. For better results, we recommend using a flat-bottomed glass or stainless steel mug. Placing a lid on the mug also helps to retain the heat. (Cups with recessed bottoms, insulated thermoses or mineral water bottles are not suitable for insulated coasters)