Canonical battery record · checked 2 September 2026

LR626 / AG4

The LR626 / AG4 family is 6.8 × 2.6 mm and alkaline. A same-size silver-oxide cell is a conditional substitute, not an automatic direct replacement.

LR626AG4LR66
Answer

LR626, AG4, LR66 are the supported exact aliases for one 6.8 × 2.6 mm alkaline button 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
Alkaline button cell
Dimensions
6.8 × 2.6 mm
Voltage
1.5 V nominal
Chemistry
Alkaline manganese dioxide / zinc
Drain context
General-purpose alkaline; sloping discharge profile
Rechargeable?
No — primary cell; do not recharge.
Capacity context
Manufacturer-, load- and cut-off-specific; use the linked datasheet for a qualified figure.
Confidence
High

Equivalence and confusion matrix

Code or familyClassificationReason
LR626 · AG4 · LR66Exact equivalentThese evidence-backed markings resolve to this one canonical record and share its cited physical and electrical specification.
SR626SW / 377Same size, different electrical familyThe 6.8 × 2.6 mm envelope matches, but the electrical families do not: Alkaline manganese dioxide / zinc at 1.5 V nominal versus Silver oxide / zinc at 1.55 V nominal. Physical fit is not equivalence.
SR626W / 376Same size, different electrical familyThe 6.8 × 2.6 mm envelope matches, but the electrical families do not: Alkaline manganese dioxide / zinc at 1.5 V nominal versus Silver oxide / zinc at 1.55 V nominal. Physical fit is not equivalence.
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

  • Devices whose battery compartment or manual specifies LR626 or a listed alias

Application context is limited to the scope stated in GP177F Alkaline Button Cell Product Specification; it is not a device compatibility claim.

This alkaline family is often sold beside a same-size silver-oxide option. The shared envelope explains the confusion, but the chemistry and voltage profile prevent an unqualified direct-replacement claim.

LR626/AG4 shares 6.8 × 2.6 mm dimensions with SR626SW/377 and SR626W/376. The first decision separates alkaline from silver oxide; the second preserves the watch-cell drain suffix.

What the code means

LR626 is the IEC-style alkaline button-cell identity. The other codes listed here are evidence-backed commercial or manufacturer aliases, not separate battery sizes.

Discharge and drain behaviour

Alkaline button cells have a more sloping discharge curve than same-size silver-oxide cells. Runtime and delivered voltage therefore depend strongly on load and the device cut-off.

Capacity context: Manufacturer-, load- and cut-off-specific; use the linked datasheet for a qualified figure.

Substitution guidance

Treat only the listed aliases as exact. Same-size silver-oxide families differ in chemistry, nominal voltage and discharge behaviour; use one only when current device or manufacturer guidance permits it.

Fact-level evidence

GP177F Alkaline Button Cell Product Specification

Published by GP Batteries; page 1, specifications and industry-standard dimensions drawing. Checked 2 September 2026. Independently presented facts only; publisher wording, layout and diagrams are not reproduced.

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.