Finnmark FD-4 Trinity 3-IN-ONE, Spectrum Plus infrared heaters, Traditional Steam Sauna Heater & Spectrum Red Light™ Therapy Combo (2 Person)Finnmark FD 4 Trinity 3 IN ONE The Trinity Combination Sauna is the only sauna available that combines Finnmarks UL listed Spectrum Plus infrared heaters combined with a traditional 120V sauna heater, plus true medical grade Spectrum Red Light Therapy. No need to compromise. Finnmarks FD 4 Trinity is the only combination sauna with true UL listed infrared heaters together with a traditional sauna heater. Furthermore, the IR panels, red light therapy,