The need to maintain proper hygiene was not limited to bathing in warm water. In the past, manufacturers of bathroom gas heaters also produced a wide range of devices in which water heated by gas flames was used to brew tea or sterilise medical instruments, among other things. This Junkers gas heater is a small apparatus of the so-called tank type, in which a certain amount of water was first heated to a high temperature and then maintained at 65°C. This solution worked best where water was used in small quantities at a time (hairdresser, hospital, doctor's office). Temperature control was carried out by a special vessel – a flat round container similar to an oil cup, which was filled with a suitable liquid (ether or alcohol). The mentioned vessel was installed on the back of the device. Under the influence of the rising temperature, the liquid in the vessel would begin to boil, and the resulting steam exerted pressure on the diaphragm that closed the gas valve. After using up some of the hot water and letting in cold water, the control element cooled down and the vapor (e.g. alcohol) pressure decreased, allowing the gas flame to increase, which reheated the water to the desired temperature.