I started my oxygen use over three years ago with a normal full flow concentrator and tanks for mobility. After being restricted to time and distance by the tanks, I discovered the Inogen One portable. Since then, a large portion of my normal life has returned. I can travel anywhere and not worry about running short of oxygen. I can continue my activities away from the house and be with family and friends. Yard work, hunting club meetings, shopping, overnight trips, flying, RV trips, boating and most anything else are all possible, thanks to the Inogen One.