The most commonly used batteries for hearing aids are called Zinc air batteries. Small silver discs, Zinc-air batteries are not rechargeable, and must be discarded after use. Hearing aid batteries come in five sizes. The right one for you depends on the style and size of your hearing aids. The hearing aid industry has color and number coded the packaging of batteries to make buying, replacements, easy choose 5-red, 10-yellow, 13-orange, 312-brown & 675- blue.