Mug Warmer Coffee Warmer with Automatic Shut Off to Keep Temperature Up to 131℉/ 55℃ with a Silicone Mug Cover Safely Use for Office/Home to Warm Coffee Tea Milk Candle Heating Wax (White)

The "Auto Shut Off" is simply a switch at the bottom of the device that is activated by the weight of the mug that is put on top of it. Of course, the trigger force is not calibrated or anything, but if you are lucky, even an empty mug will not trigger it, but if nothing sits on top, it is definitely off; with a full mug it is definitely on. In between, your mileage may vary, but it works for me. It has no other "manual" on/off switch. So it is low tech, but it works. It has a very smooth surface all over that is extremely easy to clean.

Does not keep the beverage very hot--only lukewarm.