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Home › Batteries › 397
Watch battery

397 is the same as SR726SW

1What it is2Safety3Other names4Facts5Buy it
  1. 1

    What it is

    SR726SW+ 1.55V

    397 is just another name for SR726SW. Same battery, different label, so you can buy either one.

    Search Amazon for 397As an Amazon Associate, KnowYourBatteries.com earns from qualifying purchases.

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  2. 2

    Safety first

    Keep away from children and pets

    A swallowed coin or button battery can cause serious burns inside the body within 2 hours. If you think one was swallowed, get emergency help right away.

    Swallowed one? What to do now →
  3. 3

    Names you might see in the store

    All of these are the same battery. Any of them will work.

    SR726SW
  4. 4

    Quick facts

    Size
    About as wide as a pea
    Thickness
    As thick as 3 credit cards stacked
    Power
    1.55 volts
    Keeps in a drawer for
    About 5 years
    Rechargeable?
    No, use once
    Found in things like
    Analog watches
  5. 5

    Where to buy it

    As an Amazon Associate, KnowYourBatteries.com earns from qualifying purchases.

    Amazon searchEnergizer listings, any pack sizeSearch Amazon for Energizer 397
    See results on Amazon →
    Amazon searchMulti-packs from any brandSearch Amazon for 397 (SR726SW) multi-packs
    See results on Amazon →
    Amazon searchDuracell listings, the same batterySearch Amazon for Duracell SR726SW
    See results on Amazon →

    Buttons open amazon.com 🇺🇸, picked from your country.

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See it at real size

SR726SW next to a US quarter and an AA battery. “Real size” matches your hand once your screen is set up in Measure it.

SR726SWThickness 2.6US quarterAA

What do the letters mean?

Battery names are a code. Here’s how to read 397:

3Watch-industry 300 series (Renata/Energizer numbering)
97Size and drain code. Maps to SR726SW, 7.9 × 2.6 mm

The same battery from each brand

BrandTheir name for it
Official nameSR726SW
Energizer397
Murata (formerly Sony)SR726SW
Renata (Swiss)397
MaxellSR726SW

Exact measurements

Width
7.9 mm (0.311 in)
Thickness
2.6 mm
Voltage
1.55V (empty at 1.2V)
Energy stored
32 mAh
Weight
—
Made with
Silver oxide
Works between
-10 … 60 °C
Official code
SR726SW

Questions people ask

Is 397 the same as SR726SW?

Yes. They’re the same battery with different names. You might also see SR726SW.

How long will a spare keep in a drawer?

About 5 years if it stays cool and dry.

Can I recharge it?

No. Never try to recharge it.

Which way up does it go?

Usually with the side marked “+” facing you or facing up. Look at how the old one sits before you take it out.

SR726SW+ 1.55V
SR726SWWatch battery
Search Amazon for 397As an Amazon Associate, KnowYourBatteries.com earns from qualifying purchases.

Something wrong or missing? Tell us

1What it is2Safety3Other names4Facts5Buy it