❃High Materials: This coffee mug warmer is aluminum alloy + tempered glass, it features fast heat conductivity, so the temperature of your coffee mug can reach a constant temperature of 40 ℃ in 5 minutes (Please note that this coffee mug warmer is used for keep your mug warm, but not heating it ❃Plug and Play: USB powered, you can comfortably plug in any USB compatible devices, such as laptops, travel chargers or other USB devices ❃Energy Saving: With low power consumption, this coffee mug warmer is and waterproof ❃Simple With light and switch function, this coffee mug warmer is easy to control ❃Great for Office: The insulated coffee mug warmer is designed to maintain the temperature of drinks, which is suitable for coffee lovers or office use