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Canonical battery record · checked 2 September 2026

LR1120 / 191 / LR55

The LR1120 / 191 / LR55 alkaline family is 11.6 × 2.05 mm. Same-size SR1120 watch cells use silver-oxide chemistry and separate W/SW drain classes.

LR1120191LR55AG8
Answer

LR1120, 191, LR55, AG8 are the supported exact aliases for one 11.6 × 2.05 mm alkaline button cell. No other family is treated as an automatic replacement.

Top profile · Ø 11.6 mm
Side profile · 2.05 mm high
Original proportional profiles. Scale is consistent within this diagram; screen size is not a physical ruler.
Format
Alkaline button cell
Dimensions
11.6 × 2.05 mm
Voltage
1.5 V nominal
Chemistry
Alkaline manganese dioxide / zinc
Drain context
Electronic applications including short high-rate pulses
Rechargeable?
No — primary cell; do not recharge.
Capacity context
Typical product figure near 49 mAh to 0.9 V at 15 kΩ and 21°C; conditions are material.
Confidence
High

Equivalence and confusion matrix

Code or familyClassificationReason
LR1120 · 191 · LR55 · AG8Exact equivalentThese evidence-backed markings resolve to this one canonical record and share its cited physical and electrical specification.
SR1120SW / 381Same size, different electrical familyThe 11.6 × 2.05 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.
SR1120W / 391Same size, different electrical familyThe 11.6 × 2.05 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.
SR1116SW / 366Not equivalentThe physical envelopes differ (11.6 × 2.05 mm versus 11.6 × 1.65 mm). Do not force, stack or infer equivalence from a shared diameter or code pattern.
SR1116W / 365Not equivalentThe physical envelopes differ (11.6 × 2.05 mm versus 11.6 × 1.65 mm). Do not force, stack or infer equivalence from a shared diameter or code pattern.

Supported application context

  • Calculators
  • small electronic instruments
  • devices specifying LR1120 or 191

Application context is limited to the scope stated in Energizer 191 Product Datasheet; 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.

LR1120/191/LR55 is the alkaline member of the 11.6 × 2.05 mm cluster. SR1120SW/381 and SR1120W/391 share its envelope while changing chemistry, nominal voltage and drain classification.

What the code means

LR1120 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: Typical product figure near 49 mAh to 0.9 V at 15 kΩ and 21°C; conditions are material.

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

Energizer 191 Product Datasheet

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

Open primary 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.