The compact HUUM STEEL Mini 3.5 kW sauna heater, with exceptionally short safety distances, is a wall-mounted model that is engineered for smaller sauna rooms. The STEEL Mini sauna heater is designed for sauna spaces up to 212 cubic feet (CF). Required control and sauna stones (4 boxes) sold separately. Suitable for use in small saunas with limited space Heats up to 25% faster due to internal air duct For sauna rooms from 123 to 212 cu. ft.