Special featuresCompact charger with smart technical features and safety provisions that can charge up to 4 AA or AAA batteries simultaneously. The sturdy cassette can also be used as a battery organizer, in which the batteries can be safely stored. The charger charges 4 AA 2100mAh batteries in 6 hours via a USB connection. The charging progress can be viewed via the LED indicator. The LED indicator also warns if single-use or defective batteries are inserted. Other safety features include automatic power cut-off and the detection of fully charged batteries, which helps prevent overcharging. In addition, the charger is protected against overvoltage and short-circuiting for optimal battery lifespan. Technical dataDimensions: 68x74x21.3mmWeight: 40gNumber of charging slots / Channels: 4 / 2LED indicator: 2- Green LED ON for 0.5 seconds after USB connection- Charging: Green LED blinks slowly- Fully charged: Green LED ON- Defective/Single-use batteries inserted: Red LED blinks quicklyOutput Voltage / Charging Current- D.C. 2.8V / 400mA (for AA Batteries)- D.C. 2.8V / 320mA (for AAA Batteries)USB power input: D.C. 5V / 1ACharging time (input D.C. 5.0V 1.0A min., 2 batteries):- AA battery of 2100mAh - 360 minutes.- AAA battery of 850mAh - ~180 minutes