The GCE Zen-O Lite AC Power Supply is a major lifeline for your portable oxygen concentrator. You use it to recharge your GCE Zen-O Lite battery, power your concentrator overnight while you sleep, and use it when you're watching TV—it's a vital accessory for daily use. With your Zen-O Lite portable oxygen concentrator, the AC power supply is the fastest and most efficient way to recharge the batteries while installed in your concentrator. Compared to the DC power supply, the AC power supply has a stronger current of electricity because it plugs directly into your wall outlet, speeding up the charging process. In fact, it only takes 3-4 hours to fully recharge one battery. If you are using your concentrator while recharging, it will take closer to the 4 hours mark because the electricity is also powering your concentrator. The Zen-O Lite AC power supply is compatible with standard US AC power cords, as well as European and UK power cords, making international travel simple and easy.