The Duracell 395/399 Silver Oxide Button battery is designed to provide reliable power to specialty devices like watches, medical devices, digital thermometers, and other electronics. Duracell 395/399 Silver Oxide Button batteries are guaranteed for 4 years in storage, so you can be confident these batteries will be ready when you need them. From storm season to medical needs to the holidays, Duracell is the #1 trusted battery brand.