HUUM UKU Wi-FiDigital On Off, Time, Temp Control with WiFi UKU Wi Fi sauna controller makes sauna heating very easy and comfortable. With UKU you can heat your sauna on the spot or do it from your phone through HUUM mobile app. (For HUUM sauna heaters over 11kw and up to 18kW, an UKU Ext Box is required.). Sauna heater sold separately UKU Wi Fi sauna controller makes sauna heating very easy and comfortable. With UKU you can heat your sauna on the spot or do it from