Battery

SR621SW

1.55V silver oxide button cell

SR621SW is a thin silver-oxide watch cell (about 6.8 × 2.15 mm). Retail packs often say 364. Casio EF-305 and several Seiko calibers on this site name SR621SW. LR621 / AG1 fit the same size but are alkaline — see LR621 vs SR621SW.

Chemistry: silver_oxide
Voltage: 1.55 V
Diameter: 6.8 mm
Thickness: 2.15 mm
Used by: 24 devices

Common uses: Thin watches

SR621SW Diagram

Brand-neutral outline — confirm the tray in your device.

Other names

Genuine aliases and pack labels for this battery — not substitutes of a different chemistry.

364 · SR621W · D364 · V364 · SR621

Related codes

Same battery / other names

SR621SW364

Same battery

Same battery, different label.

SR621SWD364

Same battery

Same battery, different label.

SR621SWV364

Same battery

Same battery, different label.

SR621SWSR621W

Same battery

Same battery, different label.

Same size, different battery

SR621SWLR621

Same size, different type

Fits the same slot. Different type — check the manual.

Rechargeables are not equivalents

Do not substitute a rechargeable cell unless the device documentation explicitly allows it. Silver-oxide and lookalike chemistries are not interchangeable with rechargeables by size alone.

Size family

Edge thickness in the 6.8 mm family — thicker bar means thicker cell. Not to scale. Highlighted cell is this page.

1.65 mm

2.15 mm

2.15 mm

2.6 mm

2.6 mm

Device-specific caveats

From manufacturer-backed notes on devices that use SR621SW — not generic advice.

Eco-Drive and other rechargeable cells (MT*, CTL*, SLB*, …) are excluded from this disposable CR/SR publish set.

Devices using SR621SW

2 / 24

All (24)Watches (24)Citizen (12)Seiko (9)Orient (2)

Used in

Watches24 devices

Brands: Citizen · Seiko · Orient

Compare

LR621 vs SR621SWCompare

Learn more

Testers & chargers

Optional tools that fit this cell type — only where the chemistry allows. Separate from the battery answer.

Amazon links may earn us a commission. They do not change the battery answer.

Coin cell / button cell battery tester
Quick check of CR / LR / SR button and coin cells before fitting
Buy on Amazon More tools
ZTS Mini-MBT Multi-Battery Tester
More informative state-of-charge style checks across common formats
Docs Buy on Amazon More tools
BT-168D-class digital battery tester
Budget household go/no-go checks
Buy on Amazon More tools

Coin / button cell tester
Quick check for CR / LR / SR coin cells
Open-circuit voltage alone does not prove remaining capacity.
How to test a coin cell Buy on Amazon

Buy links are optional and separate from the battery answer.

Need one?

Need a SR621SW?

Search Amazon for packs of this battery code.

Buy on Amazon Amazon UK

Buy links go to Amazon (Associates where tagged) or other affiliate programmes when available. They never change the battery answer.