The B441 compact charger, equipped with intelligent technical features and security features, can charge up to 4 AA or AAA batteries at the same time. The sturdy cassette also serves as a battery holder, in which the batteries can be stored securely.In 3 hours, the device charges 4 2100 mAh AA batteries via a USB port. The charging progress can be tracked via the LED display. It shows the charging status as well as whether disposable or bad batteries were inserted. New with this charger is the function ""Battery status check". With this function, you can quickly and easily check whether your batteries are still sufficiently charged or need to be recharged. You can thus avoid unexpected situations with flat batteries and avoid unnecessary charging of your batteries.Other safety features include automatic power-cut timer and DV full charge detection to help prevent over-charging, over-voltage, short-circuits, and battery life degradation. This versatile battery charger works via USB or a