HUUM DROP 9STU PkgDROP Series 9. 0kW Sauna Heater Package This inspired HUUM DROP sauna heater package comes complete with the award winning, compact DROP 9kW sauna heater, UKU control (WiFi optional), and sauna stones everything you need to transform your sauna space into your dream sauna sanctity. The package has been combined for use in sauna rooms up to 530 cubic feet (CF). The HUUM DROP 9STU PKG features all the necessities to give your sauna space a touch of