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379 battery (SR521SW)
SR521SW: 1.55 V silver oxide button cell, 5.8 mm × 2.15 mm, about 14 mAh (22 mWh). Same battery: 379. Also fits: LR521.
1.55 Vvoltage
5.8 mmdiameter, 0.228 in
2.15 mmthick, 0.085 in
≈ 14 mAhcapacity
SR521SW: what to know
- Common in small ladies' watches; it is 0.55 mm thinner than the 319 (SR527SW), which shares its width.
SR521SW equivalents
379
- AG0: alkaline
- LR521: alkaline
Can I use another battery instead of an SR521SW?
| Battery | Size | Volts | Works? | Why |
|---|---|---|---|---|
| LR521 | 5.8 mm × 2.15 mm | 1.5 V | Yes | Same size; alkaline is cheaper but fades sooner. |
| SR516SW | 5.8 mm × 1.65 mm | 1.55 V | Short-term | 0.5 mm thinner: may sit loose; fine short-term. |
| SR527SW | 5.8 mm × 2.7 mm | 1.55 V | No | 0.55 mm thicker: will not fit. |
| Size 10 | 5.8 mm × 3.6 mm | 1.45 V | No | Zinc-air cells need air holes; not for sealed devices. |
What uses an SR521SW battery?
- Small ladies' watches
Alkaline version: LR521 (AG0), about 7 mAh vs 14 mAh; cheaper but its voltage sags.