AirSep FreeStyle Portable Concentrator (POC) with Ultrasense. 1-3 pulse setting 3 settings- 2 hrs: 2 settings- 2.5 hours 1 setting - 3.5 hours charge time. 3 hours features: Fashionable carry case with adjustable strap. Ultra-light at 4.4 lbs unique Ultrasense technology exceptional battery life. FAA-approved for on-board, in-flight use. Optional airbelt or external power cartridge available for advance durations up to 10 hours (freestyle) hours optional harness available to convert carry case to back pack.