Advanced silver-zinc rechargeable hearing aid battery for use with ZPower Rechargeable System. Battery is shipped fully charged and ready to use out of the box, there is no need for “pre-charging”. The ZPower Rechargeable Battery provides all-day continuous power, even in advanced hearing aids with moderate streaming. The batter is eco-friendly. One ZPower battery takes the place of 100 zinc-air disposable batteries. It contains stable energy, is non-flammable and safe. Sold by the each. Batteries should be replaced annually.