The Nitecore UM4 charger is a fast and efficient USB charger that can charge up to four batteries with the option to control each bay independently. The charger has a maximum output of 1500mA in a single slot - please note, this is only achievable if using a 9V 2A QC 2.0 charging adapter. The charger features a charging programme specially optimised for IMR batteries which monitors the entire charging process, ensuring that the cut-off voltage is always within safe limits to extend the lifespan of the battery. The Nitecore UM4 has a useful LCD display which relays real-time charging information. A short press on the 'V' button will cycle through details on the charged volume and charging time, charging current and battery voltage, battery type, cut-off voltage and charging mode. The charger will automatically select from 3 charging modes when the battery is inserted, according to the battery type and capacity. Alternatively, the charging parameters can be set manually to meet various charging needs; long press the 'C' button to enter the charging setting mode. The charger offers over-discharged IMR battery restoration. When an over-discharged IMR battery is inserted, the screen will show 'EE EE'; simply long press the 'V' button to enter restoration mode. The screen will also display 'EE EE' if a short-circuited battery is inserted or the cell is the wrong way round. The Nitecore UM4 is compatible with the following IMR/Li-ion/LiFePO4 batteries: 10440, 14500, 14650, 16500, 16340 (RCR123), 16650, 17350, 17500, 17650, 17670, 17700, 18350, 18490, 18500, 18650, 18700, 20700, 21700, 22500, 22650, 25500, 26650, 26700 and the following NiMH/NiCd: AA, AAA, AAAA, C, D.