Rayovac Extra Size 13 Batteries ensure your hearing aids work at excellent level for longer time. Each package has a rotating secure dial, which helps you to remove one battery cell at a time. Each cell is attached to a tab, making it safer to swap out the battery with ease. Available in sizes 10, 13, 312 & 675, and comes in a variety of pack sizes to best suit your requirements. Suitable for all hearing aids which require battery sizes 10, 13, 312 & 675.