What makes the A10 Zinc Air battery unique is that it uses oxygen from the atmosphere. It has a small hole in the case that allows air into the battery, which is used as part of the chemical reaction. The A10 battery is not activated until the plastic seal is removed. Typical applications are hearing aids, pagers and personal medical instruments. With the AC10 high quality Zinc Air battery, you will experience fewer battery replacements, clearer tones, less distortion, and longer service life. These batteries give the highest energy density of any battery system and is environmentally safe.