The Powerex MH-C401FS 100 Min Cool Charger with Car Adapter charges 1-4 AA or AAA NiMH or NiCD batteries in approximately 100 (AA) or 60 (AAA) minutes, while keeping them cool. As an alternative to this rapid charge method, it allows for a slower, 5-hour gentle charge to keep batteries extra-cool when charging time is not a critical issue. The gentle charge also extends overall battery life. Both methods are driven by a microprocessor termination control, in order to prevent overcharging. It has a unique FLEX negative pulse charging algorithm enables the battery to accept a more complete charge, significantly enhancing battery life. The pulse eliminates memory effects, making conventional battery conditioning and cycling obsolete. It also has four independently-controlled channels charge and monitor each battery individually, charging it to its full potential without risking overcharging. * Batteries NOT included