Review on Ingecafea Coffee Mug Warmer for Desk Use - Upgraded Version with 4 Temperature Settings, 4-Hour ☕ Auto Shut Off, Waterproof Design - Ideal Gift for Christmas. Keep Your Coffee, Milk, and Tea Hot! by Danny Zapata

It keeps my coffee warm and I have used it to make tea because I always forget it in the microwave or I need to heat the kettle. My dad had a similar mug warmer that only worked when the bottom of the mug was flat. I haven't had this problem. Maybe my cups aren't round enough. If you have such a problem, its solution is to use aluminum foil for the connection. Again, this hasn't happened to me yet. I love it and it's very useful for my ADHD brain. Saves a lot of trips to the kitchen.