The Powerex MH-C-9000 is the first charger for NiCad and NiMH batteries AA and AAA with the possibility to REFRESH old batteries, charge and discharge at programable rate and analyze a battery to know its exact capacity, very often 25% difference with what is indicated on the battery

With such charger you can match batteries with REAL same capacity

If you use rechargeable AA or AAA you MUST have a MH-C9000