Function: 1. Made of high quality walnut wood and metal materials, evenly heating, safe and durable to use. 2. Powered by any devices with 5V USB output port, such as computer, desktop computer, laptop, tablet, mobile power supply and so on, easy and convenient. 3. 4. 5. Perfect for home and office use, keeping your brew warm in cold weather. Specification: Description: This mata for heating cups is made of high quality walnut wood and metal materials, heats evenly, is safe and durable to use, ma natural walnut wood grain and is smooth to the touch. It is powered by any devices with 5V USB output port, such as computer, desktop computer, laptop, tablet, mobile power supply, etc., easy and convenient. Perfect for home and office use, keeping your brew warm on chilly days. Characteristics: Made of high quality walnut wood and metal materials, evenly heating, safe and durable to use. Powered by any devices with 5V USB output port, such as computer, desktop computer, laptop, tablet, mobile power supply, etc., easy and convenient. Perfect for home and office use, keeping your brew warm on chilly days. Specification: Main Material: Wood Metal Type: light wooden grain, dark wooden grain (optional) Power: 5W Voltage: 5V Electric Current: 1000mA Maximum operating temperature: 80 Wooden grain width: ok. 16mm / 0.62 inch Diameter of metal plate: ok. 75mm / 2.95 inch Whole diameter: ok. 103mm / 4.05 inch Weight: ok. 108-109g The package includes: 1 x Cup warmer with USB cable (cups not included)