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.