361 / SR721W battery equivalent

Also sold as SR721W. 1.55 V with a flat discharge curve — the usual choice for quartz watches.

Chemistry

Silver oxide

Voltage

1.55 V

Size

7.9 × 2.1 mm

Inches

0.311 × 0.083 in

Drain

High drain (W)

Typical capacity

~24 mAh

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Equivalents by brand

Brand	Number
Renata	361
Energizer / Eveready	361
Maxell / Panasonic / Sony	SR721W
Varta	V361
Rayovac	361
Duracell	D361
Timex	X
Citizen	280-53
Seiko	SB-BK/EK
IEC	SR58
IEC size	SR721

Also known as

SR721WV361D361X280-53SB-BK/EKSB-BKSB-EKSR58SR721AG11SG11

What it fits

Watches with alarms or backlights. 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 SR721W is about 7.9 mm across and 2.1 mm thick.

Same size, different drain

These cells share the 7.9 × 2.1 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 361?

Any of these are common equivalents: 361, SR721W, V361, D361, X, 280-53, SB-BK/EK, SB-BK. They are 1.55 V silver oxide cells, 7.9 × 2.1 mm.

Is 361 the same as SR721W?

Yes — SR721W is the IEC / Japanese-brand name for the same 361 cell.

What devices use a 361?

Watches with alarms or backlights