Button cell battery Maxell SR927SW 1.55V Silver Oxide (size 399, SR57)

Maxell SR927SW is a 1.55V silver oxide button cell (size 399, also known as SR57) designed for use in compact electronic devices. It provides a stable nominal voltage and consistent discharge characteristics suitable for low-drain to moderate-drain applications. The cell's compact dimensions make it compatible with devices that specify SR927SW, SR57 or 399 size batteries, allowing straightforward replacement and maintenance.

Advantages

This silver oxide cell delivers stable voltage over most of its service life, supporting accurate timekeeping and reliable operation of small electronics. Its chemistry resists leakage under normal use and offers better capacity retention at low current draws compared with alkaline button cells of similar size. The standardized size and polarity ensure compatibility with many watches, calculators, medical instruments and sensors that require an SR927SW/SR57/399 battery.

Suitable for

• Wristwatches and horological instruments
• Calculators and small handheld electronics
• Medical devices such as thermometers and glucometers (if manufacturer permits)
• Optical instruments, sensors and small measuring tools

Key specifications

• Chemistry: Silver oxide
• Nominal voltage: 1.55 V
• Form factor: Button cell (size 399 / SR57)
• Typical applications: Low- to moderate-drain electronic devices
• Polarity: Positive top

How to use

Before replacing the battery, verify the device documentation to confirm compatibility with an SR927SW (size 399 / SR57) cell. Power off the device or remove it from service, then open the battery compartment following the manufacturer's instructions. Observe correct polarity when inserting the new cell and ensure the contact surfaces are clean and free of corrosion. After installation, secure the battery cover and power on the device to verify normal operation. Dispose of the used battery according to local regulations for battery recycling.

Usage recommendations

Store unused cells in a cool, dry place away from direct sunlight and heat sources. Avoid mixing new and used batteries or different chemistries in the same device. For devices with critical measurement or medical functions, replace the battery at regular intervals recommended by the device manufacturer and confirm proper operation after replacement.