With the Oxlife Independence AC Power Supply, you have your portable oxygen concentrator's life-line. The AC power supply allows you to re-charge batteries while you are relaxing at home or overnight while you are sleeping. It will recharge one or two batteries depending on how many you are using in the concentrator, and charging will occur whether the Oxlife Independence is on or off. Not only does the Oxlife Independence AC Power Supply recharge your batteries, it also powers your machine simultaneously on every pulse flow or continuous flow setting. Although it may take longer for your batteries to charge while you use the machine, the AC power supply will work on every setting. The AC power supply was designed to be lightweight to ensure patients like you are easily able to transport it while traveling or for day to day use. This essential accessory ensures you can maintain your oxygen therapy while keeping your batteries charged for when you need to go mobile.