Maxell SR920SW Battery (371) – 1.55 V Silver Oxide for Low‑Drain Precision Devices

The Maxell SR920SW is a silver-oxide coin cell sized 9.5 × 2.05 mm and optimized for low-drain electronics that need stable voltage and long service life. Typical uses include analog watches, calipers/micrometers, small measuring tools, and compact calculators.

Quick Specs

• Size: 9.5 mm diameter × 2.05 mm height
• Chemistry: Silver Oxide (SR)
• Nominal Voltage: 1.55 V
• Typical Capacity: ~42 mAh (at low drain)
• Operating Temperature: −10 °C to +60 °C
• Common Code: 371 (low‑drain); SR920SW

When to Choose SR920SW

• Use if your device or manual specifies SR920SW or 371.
• Best for low, steady current draw (analog watches, simple measuring tools).
• Choose for consistent voltage (flat discharge curve) that supports accurate timekeeping.

When to Consider Alternatives

• If your device specifies SR920W or 370 (high drain), use that instead—features like alarms, backlights, or multifunction movements may require it.
• If only an alkaline LR920/AG6 is available, it will fit but typically provides shorter life and less stable voltage—use silver oxide (SR) whenever possible.

Performance at a Glance

• Analog watch runtime: commonly 1–3 years depending on movement and features.
• Measuring tools (e.g., calipers): months to a year+ with intermittent use; heavy use shortens runtime.
• Voltage stability: remains near 1.55 V for most of the lifespan, then declines sharply at end-of-life.

Compatibility and Cross‑Reference

• Primary: SR920SW, 371
• Also seen as: SR920 (size family), D371, V371 (brand variants)
• Alkaline size equivalent: LR920, AG6 (shorter life/less stable)

Comparison: SR920SW vs SR920W vs LR920

Type	Common Code	Chemistry	Use Case	Notes
Low‑drain silver oxide	SR920SW / 371	Silver oxide	Analog watches, steady low draw	Best voltage stability for timekeeping
High‑drain silver oxide	SR920W / 370	Silver oxide	Multifunction watches, alarms	Supports higher pulse currents
Alkaline equivalent	LR920 / AG6	Alkaline	General fit replacement	Shorter life, less stable voltage

Installation Guide

1. Open the battery compartment using the correct tool; protect the caseback and gasket.
2. Note polarity before removal (usually + faces up).
3. Insert the new SR920SW without touching both faces—use non‑metal tweezers or gloves.
4. Confirm the gasket is clean and seated; close and test the device.

Storage and Handling

• Store in original packaging in a cool, dry place; avoid heat and humidity.
• Do not mix new and used cells or different chemistries.
• Do not attempt to recharge; risk of leakage or rupture.
• Recycle at approved collection points; tape terminals before disposal.

Pros and Cons

• Pros: Flat 1.55 V output, good leak resistance, long shelf life, precise for timekeeping.
• Cons: Not intended for high‑drain pulses; performance drops quickly at end‑of‑life.

FAQ

Is SR920SW the same as 371?

Yes. 371 is the common industry number for SR920SW (low‑drain silver‑oxide, 9.5 × 2.05 mm).

Can I use LR920/AG6 instead?

It fits, but alkaline cells typically deliver shorter runtime and a sloping voltage curve. For watches and precision tools, SR920SW is recommended.

What if my watch calls for 370?

Use SR920W/370 for high‑drain applications. If the device specifies 370, do not substitute with 371 unless the manufacturer permits it.

How long will it last in a watch?

Often 1–3 years in an analog watch, depending on the movement, features (e.g., date), and ambient temperature.

Any safety concerns?

Button cells are a choking and ingestion hazard. Keep away from children and pets. If swallowed, seek immediate medical attention.