NEW Environmentally Friendly Mercury Free Hearing Aid Batteries. Total of 48 Premium Zinc Air Batteries - The Longest Lasting Batteries for Hearing Aids. Compatible with all Size 13 and 13-A Hearing Aid Batteries. Up to 4 Year Shelf Life Original Rayovac Proline from USA - The Best in Hearing Aid Batteries. NEW Rayovac Mercury-Free Proline Advanced SIZE 13 Hearing Aid Batteries. As with any "zinc-air" hearing aid battery that is "air activated", it is highly recommended that you wait at least 60 seconds after you remove the Protective Tab before turning on your hearing aid. This will activate the battery and you will get the most out of it. Be assured you know you are buying safe, original manufacturer accessories, batteries, and replacement parts. Thank you.