Canonical battery record · checked 2 September 2026

SR927W / 399

The SR927W / 399 silver-oxide family is 9.5 × 2.7 mm. Preserve the W/SW drain designation unless current device or manufacturer guidance permits otherwise.

SR927W399V399

Answer

SR927W, 399, V399 are the supported exact aliases for one 9.5 × 2.7 mm silver-oxide watch cell. No other family is treated as an automatic replacement.

Top profile · Ø 9.5 mm

Side profile · 2.7 mm high

Original proportional profiles. Scale is consistent within this diagram; screen size is not a physical ruler.

Format: Silver-oxide watch cell
Dimensions: 9.5 × 2.7 mm
Voltage: 1.55 V nominal
Chemistry: Silver oxide / zinc
Drain context: W: higher-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

SR927W · 399 · V399Exact equivalentThese evidence-backed markings resolve to this one canonical record and share its cited physical and electrical specification.

SR927SW / 395Conditional substituteBoth are 9.5 × 2.7 mm silver oxide / zinc cells at 1.55 V nominal, but their drain designations differ (W: higher-drain profile versus SW: low-drain profile). Preserve the device-specified class.

SR920SW / 371Not equivalentThe physical envelopes differ (9.5 × 2.7 mm versus 9.5 × 2.05 mm). Do not force, stack or infer equivalence from a shared diameter or code pattern.

SR920W / 370Not equivalentThe physical envelopes differ (9.5 × 2.7 mm versus 9.5 × 2.05 mm). Do not force, stack or infer equivalence from a shared diameter or code pattern.

CR1025Not equivalentThe physical envelopes differ (9.5 × 2.7 mm versus 10 × 2.5 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 W higher-drain designation remains part of device selection.

SR927W/399 is the higher-drain 9.5 × 2.7 mm record. SR927SW/395 matches physically but retains the SW low-drain designation.

Commonly confused

SR927SW / 395 — compare all four decision fields.
SR920SW / 371 — compare all four decision fields.
SR920W / 370 — compare all four decision fields.
CR1025 — compare all four decision fields.

What the code means

SR927W 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. W: higher-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 higher-drain requirement also agree with the device specification.

Fact-level evidence

Murata Watch Battery Selection Guide

Published by Murata; page 1, SR927W 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; SR927W 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.