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Canonical battery record · checked 2 September 2026

SR626SW / 377

The SR626SW / 377 silver-oxide family is 6.8 × 2.6 mm. Preserve the W/SW drain designation unless current device or manufacturer guidance permits otherwise.

SR626SW377V377SR66
Answer

SR626SW, 377, V377, SR66 are the supported exact aliases for one 6.8 × 2.6 mm silver-oxide watch cell. No other family is treated as an automatic replacement.

Top profile · Ø 6.8 mm
Side profile · 2.6 mm high
Original proportional profiles. Scale is consistent within this diagram; screen size is not a physical ruler.
Format
Silver-oxide watch cell
Dimensions
6.8 × 2.6 mm
Voltage
1.55 V nominal
Chemistry
Silver oxide / zinc
Drain context
SW: low-drain profile
Rechargeable?
No — primary cell; do not recharge.
Capacity context
Manufacturer- and test-condition-specific; no universal capacity is asserted from the selection guide.
Confidence
High

Equivalence and confusion matrix

Code or familyClassificationReason
SR626SW · 377 · V377 · SR66Exact equivalentThese evidence-backed markings resolve to this one canonical record and share its cited physical and electrical specification.
LR626 / AG4Same size, different electrical familyThe 6.8 × 2.6 mm envelope matches, but the electrical families do not: Silver oxide / zinc at 1.55 V nominal versus Alkaline manganese dioxide / zinc at 1.5 V nominal. Physical fit is not equivalence.
SR626W / 376Conditional substituteBoth are 6.8 × 2.6 mm silver oxide / zinc cells at 1.55 V nominal, but their drain designations differ (SW: low-drain profile versus W: higher-drain profile). Preserve the device-specified class.
LR621 / AG1Not equivalentThe physical envelopes differ (6.8 × 2.6 mm versus 6.8 × 2.15 mm). Do not force, stack or infer equivalence from a shared diameter or code pattern.
SR621SW / 364Not equivalentThe physical envelopes differ (6.8 × 2.6 mm versus 6.8 × 2.15 mm). Do not force, stack or infer equivalence from a shared diameter or code pattern.

Supported application context

  • Watches specifying this exact code and drain class

Application context is limited to the scope stated in Murata Watch Battery Selection Guide; it is not a device compatibility claim.

This record belongs to the watch-cell system. Maker numbers are useful aliases, while the SW low-drain designation remains part of device selection.

SR626SW/377 is the low-drain side of the 6.8 × 2.6 mm silver-oxide pair. SR626W/376 passes size and chemistry but differs at drain; LR626/AG4 differs at chemistry and voltage.

What the code means

SR626SW identifies a silver-oxide watch cell. The W or SW suffix is part of the supported identity and records the manufacturer drain class.

Discharge and drain behaviour

Silver-oxide cells are selected for a comparatively stable working voltage. SW: low-drain profile remains material in watch applications, so a shared diameter and height do not erase the W/SW distinction.

Capacity context: Manufacturer- and test-condition-specific; no universal capacity is asserted from the selection guide.

Substitution guidance

Treat only the aliases on this page as exact equivalents. Another cell with the same dimensions is conditional at best unless its chemistry, nominal voltage and low-drain requirement also agree with the device specification.

Fact-level evidence

Murata Watch Battery Selection Guide

Published by Murata; page 1, SR626SW dimension and cross-reference row. Checked 2 September 2026. Independently presented facts only; publisher wording, layout and diagrams are not reproduced.

Corroborated against Maxell Button and Coin Battery Cross-reference Table; SR626SW row in the silver-oxide battery table.

Open primary source Open corroborating source
Not a device-fit guarantee.

Confirm the exact code, chemistry and drain requirement with the device maker. Keep button and coin cells away from children and never recharge this primary cell.