The Duracell Silver Oxide 303/357 button batteries are designed to provide reliable power to specialty devices like watches, medical devices, digital thermometers, and other electronics. These batteries are guaranteed for 4 years in storage, so you can rest assured they will be ready when you need them. To help ensure the safety of your children, they come in a child-secure package, which is nearly impossible to open without scissors. From storm prep to holiday needs, Duracell is the # 1 trusted battery brand.