The product is a pack of 8 Rayovac Crystal Clear hearing aid batteries in size 312 PR41. These batteries are designed for use in hearing aids and have a zinc-air chemical composition. With a power source of battery and a sound processing method of analog, these brown batteries are suitable for fitting in both ears. The batteries come with a CE certificate and have a voltage of 1.45V. They are replaceable and have an expiry date of 2030