Seizaiken SR721SW (362 / 361) 1.55V Silver Oxide Watch Battery – Pack of 100

## Seizaiken SR721SW (362 / 361) 1.55V Silver Oxide Watch Battery – Pack of 100

Seizaiken SR721SW is a genuine 1.55V silver oxide button cell, commonly cross-referenced under the code 362 / 361. It is manufactured by Seizaiken and is designed for analog quartz watches and other small precision electronics. This listing is for 100 x SR721SW batteries only.

This product is made for customers who want a reliable, correctly specified replacement battery for their existing watch, without guesswork over voltage or chemistry. It ships sealed to protect the contacts until you’re ready to fit it.

### Product Specifications

| **Brand** | Seizaiken |
| — | — |
| **Battery Type / Model** | SR721SW |
| **Cross Reference Code(s)** | 362 / 361 |
| **Chemistry** | Silver Oxide |
| **Voltage** | 1.55V |
| **Pack Quantity** | 100 batteries |
| **Condition** | New, sealed |
| **Recommended Use** | Analog quartz watches and other small precision electronics |

### Key Features

– Genuine Seizaiken silver oxide cell, not a generic unbranded substitute
– Stable 1.55V output for accurate, consistent watch timekeeping
– Cross-referenced against 362 / 361 for easy identification
– Supplied sealed to protect contacts during storage and transit
– Available in a 100-batteries pack to suit single replacements or bulk servicing needs

### Benefits

Fitting the correct battery chemistry and voltage matters more than people often expect: an incorrect substitute can run a watch fast, slow, or shorten the life of the movement. The SR721SW is matched to the 362 / 361 specification so your watch keeps time the way its manufacturer intended. Silver oxide cells hold their voltage close to 1.55V for most of their working life before dropping off relatively quickly near the end, which is why watches tend to keep accurate time right up until the battery needs replacing, rather than slowly losing accuracy.

### How to Confirm Fit

Watch batteries of the same physical size are sometimes sold under different code names by different manufacturers, since there’s no single universal numbering system across the industry. Before ordering, check the code stamped on your existing battery or printed inside your watch’s battery hatch, and match it against 362 / 361. If your old battery shows a different code, compare the physical diameter and thickness against the SR721SW rather than relying on the code name alone.

### Fitting Guidance & Safety

Many watches with a screw-off or snap-off case back can be opened at home with a small case-back tool, but we’d suggest a jeweller or watch specialist if you’re not confident, especially on water-resistant models, since disturbing the seal can affect water resistance until it’s re-tested. Handle button cells by the edges, avoid letting metal tools touch both terminals at once, and keep spare cells away from children and pets, as they are a swallowing hazard.

### Important Information

This listing covers the battery only; it does not include a watch, tool kit, or case-back opener. For chronographs, smartwatch hybrids, or any watch with additional electronic functions, please confirm with your watch’s manual that the SR721SW is the correct specification for that movement, as some multi-function watches are calibrated for a specific drain rate.

### FAQ

**Is this a genuine Seizaiken battery?**
Yes, this is a genuine Seizaiken SR721SW, not a generic or unbranded substitute.

**How do I check this is the right size for my watch?**
Match the code on your old battery, or the code printed inside your watch’s battery hatch, against 362 / 361.

**How many batteries are included?**
This listing includes 100 x SR721SW batteries.

**Does this come with fitting tools?**
No, this listing is for the battery cells only.

If you’re unsure which size your watch needs, get in touch with our team before ordering — we’re happy to help you cross-reference the correct battery code.