Newest EVOLUTION 15% Longer Battery Life Total of 60 Batteries Guaranteed Fresh, with the Black Evolution Battery Pack Now in Child Resistant Packaging, as required by US law Newest TFT Thin Foil Technology power one EVOLUTION Hearing aid batteries with highest energy density are the result of consistent research work and ongoing development. Our expertise here is based on the synergy of wide-ranging material research, many years of experience in cell development and our own manufacturing plant technology. Our newest development is the power one EVOLUTION, based on TFT (Thin Foil Technology). It has a very high energy density, more capacity than our well-established hearing aid batteries and therefore a longer operating life – by up to 15%. Total of 60 Batteries and Keychain Battery Holder.