Rayovac Extra Advanced Zinc Air Batteries in blue, size 675 come in a 60 batteries value pack. Rayovac Extra Advanced Zinc Air Batteries offer a particularly high energy density, whereby the same battery life can be achieved over the entire battery life. The long-lasting Rayovac Extra Advanced batteries allow you to get as much power as possible from your hearing aid and reduce the risk that you suddenly no longer have a functioning hearing aid. Rayovac Extra Advanced batteries have clear-sound technology. This innovation ensures a consistently high performance throughout the battery life. The Rayovac Extra Advanced delivers the exact amount of energy required for every hearing situation. The Clear-Sound technology ensures that your device works optimally over the entire battery life. The Rayovac zinc-air battery, as the name implies, creates power by oxidizing zinc with oxygen from the air - to activate it, just remove the tab and wait about 1 minute before installing it in your hearing aid.