LR936 vs SR936SW
The LR936 and SR936 share a 9.5 by 3.6 mm case, so either fits the same watch or device. The LR936 is 1.5 volt alkaline holding 50 to 60 mAh. The SR936SW, sold as the 394, is 1.55 volt silver oxide holding 67 to 70 mAh at a voltage that barely moves as it drains.
| LR936 | SR936SW | |
|---|---|---|
| Chemistry | Alkaline (Zn/MnO2) | Silver oxide (Ag2O) |
| Voltage | 1.5 V | 1.55 V |
| Diameter | 9.5 mm | 9.5 mm |
| Height | 3.6 mm | 3.6 mm |
| Capacity | 50-60 mAh | 67-70 mAh |
| Also sold as | AG9, LR45, L936, 194 | 394, SR45, V394, SR936W (380, high drain) |
This is the tallest common cell in the 9.5 mm watch family, sitting above the 373, 371 and 395, and its height is where the capacity comes from. It also means the diameter tells you nothing by itself. Several cells share 9.5 mm, so read the code on the battery you removed, or confirm 3.6 mm of thickness, before ordering anything.
Larger quartz movements, instruments and small medical devices are the natural home for the silver 394, because a big cell facing a low-drain circuit simply keeps going: three years or more in many analog movements. The alkaline AG9 turns up in watches too, usually as a factory fit, and in toys where a sliding 1.5 volts costs nothing anyone notices.
Names to recognise: the alkaline is LR936, AG9, LR45, L936 or 194, and the silver is SR936, 394, SR45 or V394, with the 380 as a second number covering the same case in a different drain tuning. Either silver cell fits where the other does. Moving from alkaline to silver here means 67 to 70 mAh against 50 to 60, at a voltage that holds rather than slides.