Focus portable oxygen concentrator (POC) with Ultrasense. Pulses to 3 lpm. Includes 2 rechargeable batteries, power supply and carry case. Worlds lightest POC 1.75 lbs unique Ultrasense technology most wearable POCFAA-approved for on-board, in-flight use. Operates on rechargeable battery or AC/DC power supply optional airbelt (SEPBT0171)or external cartridge (SEPBT0261) available for advance battery durations.