321 battery equivalents
The 321 is a 6.8 × 1.65 mm silver-oxide cell, used in thin small quartz watches. It's sold under several names: SR616SW.
Equivalents
| Sold as | Type | In a watch |
|---|---|---|
| SR616SW, 321 | Silver oxide, low drain | Best for an ordinary analog quartz watch |
Look-alikes that won't fit
These are also 6.8 mm across, so they look right in the pack, but the thickness is different. They aren't substitutes.
Never use a lithium coin cell in its place. Lithium cells run at 3 volts, twice what a silver-oxide watch movement expects.
Getting a 321 changed
Watch shops in our directory list battery changes from $4.99 to $115, with a median of $15, usually done while you wait. A shop has the tools to open a screw-down caseback without marking it, and can replace the gasket and pressure-test a water-resistant watch. 455 shops in the directory list battery replacement. To do it yourself, follow how to change a watch battery.
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Questions
- Can I use a 364 instead of a 321?
- No. Both are 6.8 mm across, but the 364 is 2.1 mm thick and the 321 is 1.65 mm. A thicker cell won't let the caseback or holder close, so the watch won't run reliably.
- How long does a 321 battery last?
- In a typical analog quartz watch, two to five years. It holds about 13–16 mAh; a running chronograph, a backlight or an alarm drains it faster. Unused cells keep for several years in the pack.