The Zen-O Lite external battery charger is a single-bay charger that gives you the ability to recharge batteries without plugging your concentrator into the AC or DC power supplies. The convenience of the Zen-O Lite external battery charger gives you the ability to accomplish more throughout your day, as you won't have to worry about taking unnecessary breaks or postponing plans to allow your batteries to recharge. Simply plug in your external battery charger with the 110v power cord into any wall outlet, put a battery on the charger, and let it sit to charge. Compared to the AC and DC power supplies, the external charger is not responsible for powering your concentrator at the same time, making a huge difference in how fast your battery will recharge. One of the best features the external charger has to offer is that it can recalibrate your Zen-O Lite batteries, resetting the lithium-ion cells to ensure they hold as much of a charge as possible. An LED indication system notifies you of charging status and calibration status.