Essential in order to keep your fermentation at the right temperature.
You can get away without a heating brewbelt if you can place your brew in an environment with a constant temperature of about 22 oC. Some people use the hot press; it can work if the hot water tank is insulated, and if you monitor the temperature carefully; the danger is that the temperature will rise above 26 oC. Coopers beer kit yeasts will survive up to 30 oC or more, but other yeasts will die and the brew will be destroyed.
The original 4 in 1 Brew belt heater.
It can be used on any 5 gallon vessel - bin, barrel, 2 demijohns etc.
Easy and economical to use, fitted with 240v UK mains plug.