The Maxell 394 SR936SW is a button battery that ideally suited as a replacement battery not only for watches but also for small medical devices like glucometers, heart-rate monitors, and digital thermometers. As a coin cell composed of silver oxide, the Maxell 394 maintains a stable output voltage in addition to a low self-discharge for a long service life. Additionally, it has a long shelf life of 5 years which is perfect for use straight out of the box or to store in case of an emergency replacement.