This is a ceramic plate (Bone china) that requires only one minute preheating in a full size (1200W) microwave oven. and 5 to 8 minutes after you take it out of the oven it will reach maximum temperature and your hand will not be able to withstand the heat on the surface, however you can handle it safely with the bare hands by the rim.See:
My customer told me that the plate allowed his father to eat with comfort and dignity on a plate that looks like a plate; her father has Parkinson's dicease. I have realized that the appearance of the plate is as important as its functionality; another lady from the UK needs one because her grand mother refuses to eat on those plastic plates (By the way, I am trying to develop a trustworthy connection in Europe; it could be so easily sold through Amazon in the UK, Germany or France (Peut etre je pourrais aller a Paris).
Anyway, this is a nice dinner plate adequate for formal dinners; my point is do not confuse it with plastic dishes that you have to fill with hot water; HotSmart plates are excellent steak plates and just for that reason I would buy one. They are sold as singles because people do not believe that something you microwave for only one minute is still hot after 30 minutes, they can buy one, test it see that it really works as advertized and then buy more as required.
No water inside, just a solid microwave absorbing disk I developed
My greatest satisfaction is that now it is also used for elder caregiving, and by Alzheimer's Parkinsons and ALS patients as well as by WLS patients that also need to eat slowly and last but not least, to eat slowly to avoid overeating etc. Please do not confuse HotSmarts with plastic warming plates; HotSmarts are the only functional change to the ceramic plate in centuries.
For more information just Google HotSmart
Juan J. Ramirez