SLODA LCD Rapid Advanced Intelligent Smart Individual Cell Battery Charger/Discharger for AA AAA Ni-MH Ni-CD Rechargeable Batteries Charge up to 4 batteries at a time of AAA AA Ni-MH Ni-CD rechargeable batteries Each slot is individual, 1 or 3 batteries charged possible, no need to charge batteries in pairs anymore Built-in negative delta v cut-off and short-circuit protection,prevent from overcharging Easy to use - It has LCD display so that the status of each battery's charging cycle can be easily seen and the sliding spring loaded negative pole makes inserting any type battery a breeze Unique algorithm to detect bad or defective batteries and cease charging automatically