The SR927SW is a 1.55-volt silver oxide watch battery, about 9.5 mm wide and 2.7 mm thick. Its most common equivalents are the 395 and 399, and Energizer lists them as one 395/399 cell (IEC SR57). Energizer’s battery cross-reference guide lists 395, 399, SR927SW, SR927W, SG7, V395 and GP95, among other names, as the same cell.
This guide uses Energizer’s data sheets and cross-reference guide to explain the names, the small difference between 395 and 399, and why the similar 371 is not a safe swap.
| 395 / 399 / SR927SW | |
|---|---|
| Chemistry | Silver oxide |
| Voltage | 1.55 V |
| Diameter | 9.15-9.50 mm (0.360-0.374 in) |
| Height | 2.40-2.70 mm (0.094-0.106 in) |
| Typical capacity | 54 mAh (to 1.2 V) |
| Weight | About 0.8 g |
| IEC code | SR57 |
| US (ANSI) codes | 1162SO (395), 1165SO (399) |
What is the equivalent of an SR927SW battery?
The 395 or 399, often sold together as 395/399. Energizer’s cross-reference guide lists one 395/399 cell that replaces batteries labelled 395, 399, SP395, SP399, V395, V399, GP95, SR927SW, SR927W, SG7, G7, Type LA, Type W, SB-BP and SB-EP. All of these are silver oxide cells of the same IEC size, SR57.
Codes that start with L (such as LR927) or with AG are usually alkaline cells. They are not on Energizer’s 395/399 list, and alkaline button cells are 1.5 V rather than 1.55 V, so check with the watch maker before using one.
395 vs 399: what is the difference?
They are the same size, voltage and IEC code. The difference is the job they were designed for. Energizer’s older sheets describe the 395 as designed for continuous low drain. The 399 sheet adds “high pulse drain on demand”, the kind of use found in watches with a light, alarm or other extras. The US codes differ too: 1162SO for the 395 and 1165SO for the 399.
In practice, Energizer’s cross-reference guide lists one 395/399 cell for both jobs. If your watch has a backlight or alarm and the old battery says 399, a 395/399 cell is the safe choice.
What does SR927SW mean?
- S: silver oxide chemistry
- R: round
- 927: the size, roughly 9.5 mm wide (shown as “9”) and 2.7 mm thick (“27”)
- SW: a maker’s suffix; some brands sell SW and W versions of the same size, so match your old battery if you can
Can I use a 371 instead of a 395?
No. The 371 (SR920SW) is the same width, but it is much thinner: 1.85-2.10 mm against 2.40-2.70 mm for the 395. A 371 can sit loose in a 395 holder and lose contact, and it holds less energy (35 mAh against 54 mAh, Energizer figures tested on different loads). It works the other way too: a 395 is too thick for a watch made for a 371. Our SR920SW and 371 guide covers the thinner cell.
How long does a 395 battery last?
In Energizer’s continuous low-drain test, the 395 and 399 each ran about 680 hours to 1.3 V (sheet figures). On the newer combined sheet’s 20,000-ohm test, the 395/399 ran about 710 hours to 1.2 V. These are lab figures. Real battery life depends on the watch and how often you use features like a light or alarm.
How to replace a 395 watch battery safely
- Check the code on the old battery before you buy. Many 9.5 mm cells look alike.
- Note which way up the old cell sits before you take it out, and fit the new one the same way.
- If the watch is water-resistant, consider a watch shop: opening the case means the seal needs refitting correctly.
Safety: small button batteries are dangerous if swallowed. Keep new and used cells away from children and pets, and get emergency medical help straight away if you think a child has swallowed one.
More watch battery guides: SR920SW and 371 equivalents, SR626SW and 377 equivalents, SR621SW and 364 equivalents and LR41 equivalents.
Frequently asked questions
Is SR927SW the same as 395?
Yes. Energizer’s cross-reference guide lists SR927SW as one of the names for its 395/399 silver oxide cell.
Is 399 the same as 395?
They share the same size, voltage and IEC code. Energizer’s 399 sheet adds “high pulse drain on demand” (for example, a watch light or alarm), and its cross-reference guide lists one 395/399 cell for both.
Is SG7 the same as SR927SW?
Yes. SG7 is listed with SR927SW and 395 in Energizer’s cross-reference guide.
Can I use 371 instead of 395?
No. A 371 is about 0.6 mm thinner, so it can lose contact, and it holds less energy.
What size is a 395 battery?
About 9.5 mm (0.37 in) across and 2.7 mm (0.11 in) thick.
What voltage is a 395 battery?
1.55 volts. It is a silver oxide cell.
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