The D4 automatically detects Li-ion, Ni-MH and Ni-Cd batteries, and through manual selection is also capable of charging LiFePO4 batteries. Intelligent charging circuitry selects the optimal charging mode (CC, CV and dV/dt) for a given battery and each of the D4's four microcomputer-controlled charging slots then monitors and charges the battery independently. Furthermore, an integrated digital LCD screen clearly displays charging progress, voltage, current and time while an intelligent automatic power-off function terminates current when charging is complete. The Nitecore D4: The world's most advanced fully-automatic digital charger. It's as simple as insert, detect and charge. (Equipped for in-car charging ) Nitecore IMR 18650 NI18650A 2000mAH rechargeable batteries Capacity: 2000 mAh|Type: 18650|Voltage:3.6V, 7.2 Wh Maximum continuous discharge current 30A NOT protected against over-charging, over-discharging or short-circuit so observe : do not discharge at below 2.75V, do not charge at above 4.2V, do not short circuit. AA to D Battery converter spacers These allow use of rechargeable AA batteries in D battery equipment This bundle includes -Nitecore D4 Digicharge universal home/in-car battery charger -Four Nitecore IMR 18650 NI18650A 2000mAH rechargeable batteries -2 X EdisonBright AA to D type battery spacer/converters