1.55 V silver oxide
SR721SW / 362 battery equivalent
BuySR721SWSilver oxide · 1.55 V · 7.9 × 2.1 mm
Safe swap, same cell: 362 · V362 · 280-29 · SB-AK/DK · 1158SO
Not proof of this cell: D361/362 · SR721 · SR58. The cited chart prints these codes for SR721W (high drain) as well, so they do not say which one you have. Match the full code on the old cell, including the drain suffix.
Can I use one of these instead?
- SR721WFits, read noteSame size and chemistry, different drain class
- SR716SWDo not swapDifferent thickness
- SR726SWDo not swapDifferent thickness
- SR726WDo not swapDifferent thickness
- SR714SWDo not swapDifferent thickness
- SR712SWDo not swapDifferent thickness
- SR731SWDo not swapDifferent thickness
- LR41Do not swapDifferent thickness
Also printed as: 362
1.55 V · 7.9 × 2.1 mm · Silver oxide, low drain (Renata scope chart)
SR721SW is a listed designation for this silver oxide, low drain (Renata scope chart) cell, 1.55 V, 7.9 × 2.1 mm. Figures below are copied from the datasheets and charts linked at the bottom.
| Chemistry | Silver oxide, low drain (Renata scope chart) |
|---|---|
| Nominal voltage | 1.55 V |
| Diameter × height | 7.9 × 2.1 mm Renata scope chart, millimetres |
| Designation on the datasheet | ANSI / NEDA-1158SO, IEC-SR58 |
| Drain class | low drain, as printed by Renata |
| Weight | Energizer 0.42 grams (0.015 oz.) |
Size check at real size
Lay the old cell on the outline. This shows the top outline (diameter) and the side outline (height) at 1:1 once the screen is calibrated.
SR721SW outline, 7.9 × 2.1 mm. Not a photograph, drawn from the figures above.
Calibrate this screen
Screens scale pages differently, so true size is only true after calibration. Hold a bank card or ID card (85.60 mm wide, ISO/IEC 7810 ID-1) against the bar and slide until the bar is exactly as wide as the card.
Saved in this browser only.
All cells on one true-size sheet
When printing, set scale to 100% or Actual size, not Fit to page.
Capacity
These are not one test repeated. Capacity varies by brand, load, temperature and cutoff.
| Source | mAh | Test as printed |
|---|---|---|
| Renata | 23 | Capacity column of the July 2016 scope chart. The chart does not print the load or cutoff for this row. |
| Energizer | 27 | to 1.3 volts; rated at 68k ohms continuous at 21ºC |
Cross-reference
Each code is printed on the cited chart. A shared outline is not, by itself, the same cell. Renata's chart puts Maxell, Panasonic, Sony and Toshiba in one column, so those four names share the code shown.
| Where it is printed | Code |
|---|---|
| Energizer | 362 |
| Maxell, Panasonic, Sony, Toshiba | SR721SW |
| Varta | V362 |
| Rayovac | 362 |
| Duracell | D361/362 |
| Timex | S |
| Citizen | 280-29 |
| Seiko | SB-AK/DK |
| IEC code on the Renata chart | SR721 Printed as 'SR721 (SR58)'. |
| IEC code on the Renata chart | SR58 Printed as 'SR721 (SR58)'. |
Devices named on the Energizer guide
Watches. See watches.
Same outline
- SR721W Silver oxide, high drain (Renata scope chart) · 1.55 V · 7.9 × 2.1 mm
Silver oxide watch and instrument cells
These are zinc/silver oxide button cells. Energizer's product sheets print a nominal 1.55 V. The silver-oxide application manual puts the open-circuit voltage at 1.6 V and the operating voltage, at ordinary drains, at 1.55 V or higher. The curve stays flat for most of the discharge. That is why a watch, a glucose meter, or a caliper that was specified for silver oxide keeps time or stays in calibration longer than it does on an alkaline cell of the same outline.
Renata splits each common outline into a low-drain cell and a high-drain cell. The low-drain code ends in SW (SR626SW is Renata and the trade number 377). The high-drain code ends in W (SR626W is 376). Energizer's manual explains the underlying choice without using those suffixes: a potassium hydroxide electrolyte carries a heavier current than a sodium hydroxide electrolyte, and the sodium hydroxide cells are the easier ones to seal. The manual does not print 'SW means NaOH'. This index does not add that sentence. It follows Renata's low-drain and high-drain labels, which are printed in the scope chart.
The two drains fit the same well. Energizer's cross-reference often puts the pair on one line (377/376, 357/303, 371/370) under 'replaces batteries labeled as'. Read that as a fit list. If the old cell or the watch case says 377 or SW, buy the low-drain cell. If it says 376 or W, buy the high-drain cell.
Energizer still prints the older short IEC codes on the datasheet: SR66 for the 6.8 × 2.6 mm cell, SR44 for the 11.6 × 5.4 mm cell, and so on. Renata prints the longer code, SR626SW or SR44W. Both appear on the page. The short code is shared by the low-drain and high-drain twins, so 'SR44' alone is not enough to pick 357 or 303. The suffix, or the three-digit number, is.
Sources
Last verified 2026-10-29.
- Renata scope of supply, consumer, part no. ZW9843, version 07.2016 Renata SA, checked 2026-10-29
- Energizer silver oxide application manual, 11/06/01 Energizer, checked 2026-10-29
- Energizer 362 product datasheet (362.pdf) Energizer, checked 2026-10-29