Button Battery Watch Battery SR521SW x 4 (#147)

LR521 SR521SW Compatible 4-Pack

Compatible Button Batteries
SR521SW/ag0/379/lr521/sr521/ag521/s521e/521a/SG-521S/sr63/379A/gp379/v379/379x/d379

The packaging may indicate Oxide Silver Battery SR521SW, but due to some listings showing Alkaline Battery, these are being sold as LR521.

Generally, SR model numbers refer to oxide silver batteries, which have a stable voltage ideal for watches but are more expensive. For simple analog watches, consider using these more affordable alkaline compatible batteries.

The model numbers listed below are all different designations for the same standard battery. Generally, batteries with the same model number are compatible, even if they are from different manufacturers.
SR521SW/ag0/379/lr521/sr521/ag521/s521e/521a/SG-521S/sr63/379A/gp379/v379/379x/d379

Manufacturer: Koonenda
Type: Alkaline Button Cell Battery
Model Number: LR521 (379)
Nominal Voltage: 1.55V
Size: 5.8mm x 2.15mm
Recommended Expiration Date: 2032

((Important Notes for Battery Replacement))
The positive (+) terminal of this battery is on the top (where the model number is engraved), and the negative (-) terminal is on the bottom.
Electricity flows when the positive and negative terminals are connected (even when held by hand).
If you use metal tweezers to grip the battery from top to bottom, it will cause a short circuit. For oxide silver batteries (SR series), this can completely discharge the battery in less than 30 seconds (or about 10 seconds for batteries with smaller capacity).

★The most crucial thing to avoid is gripping the battery from top to bottom. For oxide silver batteries (SR series), always grip the sides.

While plastic or non-magnetic tweezers are available, it is fundamentally recommended to always grip button batteries by their sides.