397 / SR726SW battery equivalent

Also sold as SR726SW. 1.55 V with a flat discharge curve — the usual choice for quartz watches.

Chemistry

Silver oxide

Voltage

1.55 V

Size

7.9 × 2.6 mm

Inches

0.311 × 0.102 in

Drain

Low drain (SW)

Typical capacity

~32 mAh

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Equivalents by brand

Brand	Number
Renata	397
Energizer / Eveready	397
Maxell / Panasonic / Sony	SR726SW
Varta	V397
Rayovac	397
Duracell	D397
Bulova	607
Timex	N
Citizen	280-28
Seiko	SB-AL
IEC	SR59
IEC size	SR726

Also known as

SR726SWV397D397607N280-28SB-ALSR59SR726SG2

What it fits

Analog watches. Confirm the printed number or measure the old cell before you buy — a 0.5 mm height difference will not seat correctly.

IEC names encode chemistry and size. SR is silver oxide, LR is alkaline, and CR is 3 V lithium. The digits are diameter and height in tenths of a millimeter, so SR726SW is about 7.9 mm across and 2.6 mm thick.

Same size, different drain

These cells share the 7.9 × 2.6 mm can. Low-drain (SW) is for simple analog watches. High-drain (W) handles lights, alarms, and chronographs. A modern multi-drain cell can usually cover both.

FAQ

What battery replaces a 397?

Any of these are common equivalents: 397, SR726SW, V397, D397, 607, N, 280-28, SB-AL. They are 1.55 V silver oxide cells, 7.9 × 2.6 mm.

Is 397 the same as SR726SW?

Yes — SR726SW is the IEC / Japanese-brand name for the same 397 cell.

What devices use a 397?

Analog watches