Finnmark Designs Trinity 48" 2-Person 3 In One Combination Sauna With Infrared, Steam and Red Light TherapyThe 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, and the traditional sauna