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Specialty silver-oxide

4SR44 battery: equivalents & specs

The 4SR44 is a 6.2 volt cylindrical battery built from four stacked SR44 silver-oxide cells, 13 mm across and 25.2 mm long. Known historically as the PX28 or 544, it powered a generation of film SLRs and still serves dog collars and instruments.

4SR44 battery drawing: 13 mm across, 25.2 mm tall 4SR44 25.2 mm ⌀ 13 mm
4SR44, side view, drawn to scale: 13 mm across, 25.2 mm tall.
Voltage
6.2 V
Size (D×H)
13 × 25.2 mm
Chemistry
Silver oxide (Ag2O), 4-cell stack
Capacity
150-180 mAh

Same battery, other names

Every code below is the exact same cell as 4SR44. Any of them will fit and work identically.

PX28544V28PX4G1328PX

Compatible replacements

  • 4LR44 / A544: Alkaline version at 6.0 V; cheaper, shorter-lived, fine for dog collars and film cameras with bridge meters.

Buying and replacement notes

Three chemistries share this form factor: the silver-oxide 4SR44 (6.2 V), the alkaline 4LR44 (6 V) and the lithium 2CR1/3N (6 V). Cameras with voltage-sensitive meters were designed around the silver version's stable output, so it remains the best choice for accurate metering in classics like the Canon AE-1. For dog training collars, the cheaper alkaline works fine and is what most replacement packs contain.

Commonly used in

vintage film camerasdog training collarsmedical instrumentsinsulin pumps (older)

Need a replacement?

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Comparisons

4LR44 vs 4SR44

⚠️ 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

What replaces a PX28 battery?
The PX28 is the 4SR44, still made by Duracell and others as the 544. The alkaline 4LR44 (A544, PX28A) fits identically at 6 V, and the lithium 28L (2CR1/3N) covers the same slot. For vintage camera meters the silver-oxide original gives the most stable readings.
Is the 4SR44 just four SR44 cells?
Electrically yes: four 1.55 V SR44 cells stacked in a sleeve for 6.2 V total. In an emergency, four loose SR44s taped in series will run a device, but the factory package aligns and insulates the stack properly, so buy the real 4SR44 for regular use.
Silver, alkaline or lithium in this size: which should I buy?
Silver oxide (4SR44) for cameras with voltage-dependent light meters. Alkaline (4LR44) for dog collars and anything tolerant of gradual voltage decline; it is cheapest. Lithium (2CR1/3N) for cold weather and long standby, where its shelf life and temperature range win.