Rayovac Extra Advanced Zinc Air Batteries in yellow, size 10 come in a 60 batteries. Rayovac Extra Advanced hearing aid batteries take advantage of our new Active Core Technology; a breakthrough new cell design which maximises internal space to hold more active ingredients, ensuring our batteries are the longest lasting on the market*. An advanced anode increases battery life and ensures long lasting performance throughout the life of the battery. The new design delivers energy where its needed, prolonging the life of the battery and ensuring a consistent and precise listening experience. The tabs are 25% larger than our standard tab design, and ergonomically designed to make changing your hearing aid battery easier. Active Core Technology is a major step forward in the world of hearing aid battery power.