The main difference between your experience using FlexBeam vs using an infrared sauna is that FlexBeam does not emit heat.
FlexBeam uses red and near-infrared LEDs for maximum effects. An infrared sauna uses light of different wavelengths which also emit heat. The principle on which they work is quite different.
Read more about why we chose to create FlexBeam and not another infrared device here: What Is the Difference Between Red Light Therapy and Infrared Sauna?