Durability and reliability. Two important criteria for buying the best and most affordable button batteries for your hearing aid. GP is a renowned battery manufacturer that has excellent button cells for a variety of hearing aids. The colour of the type 13 button cells is orange. A zinc air button cell for hearing aids with a diameter of 7.9 mm and a height of 5.4 mm. The button cells cut off among the best during endurance tests. To give a guide: with normal daily use (12 hours per day), the service life is about 11 days. The batteries work perfectly in both very cold weather and extreme heat. The voltage is 1.45 volts. The batteries are not rechargeable. The handy blister pack contains 6 button cells. Tip: Always keep a set of batteries in stock so you can change them easily. GP has a very large range of button cells that work perfectly in terms of reliability and safety. You can avoid leaks by always disposing of empty batteries immediately. Always keep button cells out of reach of children. Store at room temperature.