Energizer 357/303 Batteries (3 Pack) Button Cell Batteries Energizer 357/303 Batteries provide reliable long lasting power to your important devices. Count on these button cell batteries to power your electronics whether you need batteries for the kitchen scale calculators or your keyless entry system. These Energizer batteries also provide dependable power for medical devices like your glucose monitor or heart rate monitor. Each 357/303 battery pack holds power for up to 5 years in storage letting you keep a ready supply of replacement batteries. Plus these batteries contain no mercury making them a more environmentally conscious choice. Count on Energizer specialty batteries to provide long lasting power when you need it most.