Review on ☕️ HOA Coffee-Mug-Warmer: Smart Drink-Warmer Cup for Desk with Adjustable Temperature, Auto Shut Off - Enjoy Hot Drinks Anytime! by Dominique Garrett

fairly simple product, easy to use. You can switch between low and high temperature settings by clicking on the high temperature icon. I use it every day because I can't finish my cup of coffee before it's cold. I've been using it for about 3 months with no problems. I will say that this works best with cups that have a perfectly flat bottom. You want as much of the cup as possible to be in contact with the device. But even with a slightly concave bottom, it works well if you crank it up to high settings.