Those who opt for a headset that is slightly lighter, which has to adopt the standard battery in the AA or AAA size. Since the special batteries the manufacturers are not manufactured in such numbers, one must unfortunately accept a higher price in purchasing. For this, however, I get the same 2 new batteries. The batteries of the original equipment have 4 years well perform their duties. So far is weakening even one of the two "Erstakkus". And in everyday use! Thus I have operating costs of not even 1 cent per day and battery. Since I know the life of AA and AAA batteries, I dare say that I would probably have gone worse and more expensive with this system ...