Household button battery MAXELL SR521SW (Silver-Oxide) — 2.15 mm height, 5.8 mm diameter

MAXELL SR521SW (Silver-Oxide) is a single-use button cell engineered for small electronic devices that require a stable operating voltage in a compact form. With a height of 2.15 mm and a diameter of 5.8 mm, this SR521SW (521) size battery delivers consistent power for low-drain applications such as watches, calculators, medical instruments and small sensors. The silver-oxide chemistry provides high energy density per unit volume and a steady discharge profile appropriate for timekeeping and precision electronics. This cell is manufactured without mercury and is intended for disposable, single-use applications with responsible end-of-life disposal.

Advantages

Silver-oxide construction offers a stable 1.55 V output and reliable performance across the typical life of the cell, making it suitable for devices that require consistent voltage. The compact 5.8 mm diameter and 2.15 mm height make it compatible with a wide range of miniature housings. Mercury-free manufacture reduces environmental impact while maintaining the long-life characteristics expected from silver-oxide watch cells. The chemistry and build support low self-discharge and steady discharge under low-drain conditions.

Suitable for

• Quartz wrist watches and timepieces
• Calculators and basic handheld electronics
• Small medical devices and monitoring sensors
• Hearing aid style electronics and small measuring instruments
• Backup memory and RTC (real-time clock) modules in compact devices

Key specifications

• Chemistry: Silver-oxide
• Nominal voltage: 1.55 V
• Typical capacity: ~16 mAh (low-drain conditions)
• Height: 2.15 mm
• Diameter: 5.8 mm
• Single-use (non-rechargeable)
• Mercury-free construction
• Manufacturing origin: Japan

How to use

Install the cell into the device according to the maker's polarity markings, ensuring correct orientation of positive and negative terminals. Handle the battery with dry hands or non-conductive tweezers to avoid short circuits. After insertion, verify proper contact and device operation; for timepieces, allow the movement to settle for a few minutes. Replace with the same size and chemistry (SR521SW silver-oxide) to preserve device performance and avoid compatibility issues.

Usage recommendations

Store unused cells in a cool, dry place away from direct sunlight and heat sources. Keep out of reach of children. Dispose of used batteries in accordance with local regulations and recycling schemes; do not incinerate. If a device will not be used for an extended period, remove the battery to prevent leakage and potential damage.