New in box. 10 pack of 4/pack #312 button battery. The Duracell Activair Hearing Aid Batteries in Size 312 are disposable batteries with a brown zinc-air chemical composition. They have a voltage of 1.45V and a battery capacity of 4 amp hours, ensuring a long-lasting power source for hearing aids. With an expiration date of 2027-04. Suitable for daily living aids, these Duracell batteries offer a convenient and efficient solution for maintaining a healthy and active lifestyle.