Useful and does what it should, however, the booklet was confusing - it refers to a on/off switch - there isn't one - the only way to switch the tray on is by plugging it in and switching on the socket! It also refers to a green light when the tray has reached temperature - mine hasn't got a green light, I can only see a yellow/orange light! I also decided that it was best not to use the tray actually on the table as my guests kept burning themselves as they reached over to the dishes on top - a 'heatproof' lip around the edge of the tray would have been useful and avoided these accidents, It would have also prevented the dishes from sliding off as they did tend to move about a bit which was worrying. A light which stays on whilst the tray is hot would also have been useful as unless you touch it you don't know whether it is has cooled down enough to put away etc, maybe alight which dims or changes colour as the tray cools? Overall pleased, but I would reiterate common sense and caution when using!