The HUUM CLIFF 11kW sauna heater is a slender electric sauna heater with remarkably small safety distances, which makes it perfect for saunas with limited spaces. The Cliff 11kW sauna heater is designed for saunas up to 566 cu. ft. Required Control and sauna stones (5 boxes) sold separately Suitable for use in saunas with limited space Heats up to 25% faster due to internal air duct For sauna rooms from 354 to 566 cu. ft. Works with UKU controls (sold separately) Works with UKU extension box (sold separately) 165 lb.