4 aluminum panel pressure system, enamel hot water boiler, 300 liter hot water capacity. There is no need to put it on the roof of the house to use it because it is pressurized. Even if it is placed on the floor, the house on each floor is flooded with cold water pressure on any floor. Can be integrated into radiators and similar appliances to heat a boiler or house. There is an increase in electrical resistance for the winter months. Resistant to frost up to minus 25 degrees.