InogenOne G4 portable oxygen concentrator with extended battery

The Inogen One G4 is one of the smallest, lightest and quietest portable oxygen concentrators available today. Pulse dose delivery system
Three flow settings 1, 2, 3

Battery Duration (single battery): Up to 2.7 hours
Recharge approximately 3 hours with AC or DC power
Duration (double battery): Up to 5 hours
Recharge approximately 5 hours with AC or DC power