... below 42dBA Micro Sd card large LCD 3L PSA oxygen concentrator (generator) OT-Pro for oxygen therapy, LTOT. Features:* ... low pressure temperature, low oxygen concentration*Information display: Color-LCD for Type OT-Pro.* Oxygen concentration indicatorGreen, yellow, red bar ... the LCD and Realtime oxygen concentration display for Type: OT-Pro.*Intelligent fault diagonis.* Micro Sd card, 2GB, a big log ...