CellChart
Silver-oxide watch (SR)

SR726SW battery: equivalents & specs

The SR726SW is the 397: a 1.55 volt silver-oxide watch battery, 7.9 mm across and 2.6 mm tall, holding just over 30 mAh. Its high-drain twin in the same case is the 396 (SR726W), the pick for chronographs and watches with power-hungry features.

SR726SW battery drawing: 7.9 mm across, 2.6 mm thick SR726SW 1.55V + ⌀ 7.9 mm 2.6 mm
SR726SW, face and side profile, drawn to scale: 7.9 mm across, 2.6 mm thick.
Voltage
1.55 V
Size (D×H)
7.9 × 2.6 mm
Chemistry
Silver oxide (Ag2O)
Capacity
30-33 mAh

Same battery, other names

Every code below is the exact same cell as SR726SW. Any of them will fit and work identically.

397SR59V397SR726W (396, high drain)

Compatible replacements

  • LR726 / AG2: Alkaline same-size cell; a short-life stand-in for non-critical gadgets.

Buying and replacement notes

The 397/396 pair illustrates the SW/W split well: identical dimensions, different electrolytes. Sports chronographs frequently specify the 396 because stopwatch stepper motors pull current spikes that a low-drain cell handles poorly. In a simple three-hand watch the 397 lasts longest. The alkaline AG2 fits the recess but is the budget option for toys rather than timepieces.

Commonly used in

analog quartz watcheschronograph watches (396)small instruments

Need a replacement?

Shop SR726SW batteries on Amazon →

⚠️ Keep away from children. Swallowed button batteries, especially 20 mm lithium coins, cause severe injury within hours. If a child swallows one, call the 24/7 National Battery Ingestion Hotline (US) at 800-498-8666 or poison control at 800-222-1222 immediately. What every parent should know.

Frequently asked questions

Are 396 and 397 the same battery?
Same size, different drain rating. Both are SR726 silver-oxide cells at 7.9 x 2.6 mm and 1.55 V. The 397 (SW) suits low-drain analog watches; the 396 (W) is built for high pulse loads such as chronographs. Each fits the other's slot physically.
What is the alkaline equivalent of the 397?
The AG2, also marked LR726, LR59 or 196, matches the 7.9 x 2.6 mm dimensions at 1.5 V alkaline. It works in toys and novelty items, but in a watch it delivers perhaps half the life of a 397 and lets timekeeping drift as its voltage sags.
How long does a 397 last?
Two to three years in a standard analog quartz watch. In a chronograph used with the stopwatch running often, a correctly fitted 396 may still only last one to two years, since chrono motors multiply the average current draw considerably.

More Silver-oxide watch (SR) cells

SR416SWSR512SWSR516SWSR521SWSR527SWSR616SWSR621SWSR626SWSR716SWSR721SW