UKU Wi-Fi Mirror sauna controller makes sauna heating convenient and comfortable. With UKU you can heat your sauna on the spot or do it from your phone through HUUM mobile app. UKU comes with several safety and extra features for a pleasant sauna experience. HUUM UKU Mirror is designed for use with sauna heaters up to 11kW (For HUUM sauna heaters over 11kw and up to 18kW, an UKU Ext Box is required.).