Sony 399/395 (SR927/W/SW) Silver Oxide 0%Hg Mercury Free 1.55 volts batteries. Sony was the first Corporation to provide the first mercury-free silver oxide battery to consumers. Silver oxide batteries are primary cells that have a high energy/weight ratio. Silver oxide is used as the positive electrode (cathode) while zinc is used as the negative electrode (anode) with an alkaline electrolyte. Sony silver oxide batteries provide extremely high quality, compact batteries for the high-performance devices today. Sony also ensures consistent reliability and performance in every cell. While Silver Oxide batteries are known mainly for wrist watches the application usage due to the high energy density and discharge characteristics have given the cells a broad range of application usage. Applications: Insulin Pump, Watches, Calculators, Electronic Clinical Thermometers, Remote Controllers, Portable Gaming Systems, Keyless Car Remotes, Radios, Bike Lights, Portable GPS Systems/Bike Computers, Computer/Communication Equipment, cameras, and many other devices.