A slim profile tray that happily heats up a full 25 litre fermenting vessel to a comfortable temperature about 9 degrees above room temperature. It has a quick heat up time and is very economical to use. This 25 watt heater costs about 10 cent a day to run and will speed up your brewing when used in cooler rooms or help to start off fermentation, especially useful for brewers who have been banished to the garage or the shed by she who must be obeyed. The entire tray is wipe clean plastic. A helpful orange LED light indicates when the unit is powered up. Great bit of kit