Eliminating need to change and carry multiple oxygen bottles, LifeChoice ActiVox Portable Oxygen Concentrator (POC) comes in 3 and 4 L models with AC/DC power supplies, carrying bag, cannula, battery level indicator, pushbutton oxygen flow release, and low oxygen level alarm LED. PULSE-WAVE Delivery technology controls flow of oxygen so that max oxygen dose reaches lungs, and Auto Mode Technology automatically adjusts breath trigger sensitivity to support breath depth and rates.