HI, my last pulmonlogist had me rent the finger monitor to sleep with. She determined that I needed 2L of O2 at night. When I go to pulmonary rehab, they use the band on my forehead to measure my O2. There tends to be a 4–5-point difference between my finger and my head with my finger much lower. They are telling me that my forehead is the most accurate. Given this, how was the nighttime sleep reading accurate if my fingers do not measure accurately? I have asked for a sleep test which I'm scheduled for.