Review on ☕ USB Metal Constant Temperature Heating Coaster - Insulated Mug Warmer, Creative Heating Coaster for Coffee Mugs - Desk Coffee Mug Warmer (Black) by Ryan Nguyen

Fast shipping, fast receipt. The device is smaller than expected. The photo and video show a standard 12-ounce straight-sided mug that barely fits. Can't get any wider at all. I don't like that I have to be very careful when setting the mug down so it sits flat on the warmer burner, which is about 3" in diameter. Heats up fairly instantly and keeps the drink from getting cold, but definitely doesn't keep it "hot". I believe most devices that plug into a USB port have this problem. A smaller cup can work more efficiently. Also, as shown in the video, the cable is quite long.