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Silver-oxide watch (SR)

SR41 battery: equivalents & specs

The SR41 is a 1.55 volt silver-oxide cell, 7.9 mm across and 3.6 mm tall, with about 45 mAh. It sells as the 392 (SR41W, high drain) and the 384 (SR41SW, low drain), and it is the premium replacement for the everyday alkaline LR41/AG3.

SR41 battery drawing: 7.9 mm across, 3.6 mm thick SR41 1.55V + ⌀ 7.9 mm 3.6 mm
SR41, face and side profile, drawn to scale: 7.9 mm across, 3.6 mm thick.
Voltage
1.55 V
Size (D×H)
7.9 × 3.6 mm
Chemistry
Silver oxide (Ag2O)
Capacity
42-45 mAh

Same battery, other names

Every code below is the exact same cell as SR41. Any of them will fit and work identically.

392384SR736SR41W (392)SR41SW (384)

Compatible replacements

  • LR41 / AG3: Alkaline same-size cell, the common thermometer battery; the SR41 outlasts it with steadier voltage.

Buying and replacement notes

Ask for this size at a pharmacy and you will usually be handed a 392, the number most makers print largest. The 384 is the same cell tuned for low-drain analog watches. Compared with the alkaline LR41 it offers half again the capacity and a flat discharge, which is why thermometer and instrument makers list it as the preferred cell even though the alkaline works.

Commonly used in

watchesdigital thermometersmedical devicessmall instruments

Need a replacement?

Shop SR41 batteries on Amazon →

Comparisons

LR41 vs 392

⚠️ Keep away from children. Swallowed button batteries, especially 20 mm lithium coins, cause severe injury within hours. If a child swallows one, call the 24/7 National Battery Ingestion Hotline (US) at 800-498-8666 or poison control at 800-222-1222 immediately. What every parent should know.

Frequently asked questions

Are 392 and 384 interchangeable?
Physically yes: both are SR41 silver-oxide cells at 7.9 x 3.6 mm and 1.55 V. The 392 (W) is designed for higher pulse currents, the 384 (SW) for steady low drains like analog watches. Fitting either in the other's role works with slightly reduced life.
Can the 392 replace an LR41?
Yes, directly. The 392 matches the LR41's dimensions exactly and improves on it: about 45 mAh versus 30, and a stable 1.55 V instead of a slow decline from 1.5 V. Thermometers, watches and meters all run longer and more accurately on it.
How long does a 392 last?
In a watch, two to three years. In a digital thermometer used a few times a week, several years, since each reading draws current for under a minute. Continuous loads such as lighted gadgets drain any cell this size in hours, regardless of chemistry.

More Silver-oxide watch (SR) cells

SR416SWSR512SWSR516SWSR521SWSR527SWSR616SWSR621SWSR626SWSR716SWSR721SW