Rayovac Extra Size 312 Batteries$29.99 RAYOVAC®, the #1 Manufacturer of Hearing Aid Batteries, now brings you Clear Sound Technology. Raising the benchmark of product innovation and providing consistent, quality performance through the whole life of the battery. Size 312 batteries offer the perfect compromise between compact size and battery life, with an emphasis on smaller size. They are sold in boxes of 80. Quantity Add to cart Description 37¢ per battery! Size 312 pack of 80 batteries Three Year Date Code- longest available Larger Tab Design World’s Longest Lasting Battery Made in U.S.A.