There is nothing extraordinary about the Energizer CHM4AA NiMH/NiCd battery charger, unless you think a charger working solidly for seven plus years is extraordinary. It can fit into an two prong wall socket, although its size may rob you of some slots on an extension cord. This charger is designed to charge many types of batteries: 9-volt (can charge two), AA (charges four), and AAA (charges four). The charger has a red indicator light that goes on when you start the charging cycle, and goes off when the cycle is completed. The charger is designed to house batteries in compartments. It is because of this layout, I believe, that the charger charges AAs and AAAs in pairs only (you can't charge a single or three.) You can, however, charge a single 9V battery, since each 9V slot accomodates a single battery. My assumption regarding the AA and AAA paired charging is based on the red light that only goes on when a compartment is fully filled. The charger charges batteries in a 15 hour cycle. The only indicator of a completed charge is the red indicator light going out. A countdown clock might be too much to ask for, but I wish there was at least an auditory notifier (a ding), as sometimes I forget to get my batteries out 15 hours later. But overall, it does exactly what it is designed to do, so I cannot complain.