This battery will work as both 391 OR 381.
This 391/381 Sony Battery is used to replace SR1120W style batteries commonly used in popular watch brands such as Casio, Timex, Swatch and Fossil, or other devices like calculators, cameras and medical instruments.
This battery has a nominal capacity of 50 mAh, which is a measurement of energy capacity of the battery. In general, a higher mAh indicates longer battery life.
This battery replaces the following equivalent batteries
These are low drain batteries, ideal for devices that use low power over a long periods of time like analog watches, TV remotes and alarm clocks. High drain devices use continuous power over low time with peak usages like digital watches with backlights and handheld game systems.
Sony Watch Batteries are the premier source of ultra-compact, long lasting power for all of your watches. Compatible with a wide variety of watch styles and manufacturers. Most major luxury watch brands rely on Sony batteries to power their designs. Sony 's state of the art production ensures leak-proof batteries thanks in part to a newly designed sealing process. You won't find any crusty battery goop in your watch when you use a Sony battery.
Redesigned battery packaging ensures the expiration date is always visible so you can be sure you will always have the most recently produced batteries. Sony Replacement Batteries have an extended shelf life, and last up to 10 years when stored at proper temperatures, ideally at 73.4℉.
Enjoy Quantity Discounts on all Sony Watch Batteries. The more you buy, the more you save. Always have extra Watch Batteries on hand, you never know when you'll run out of juice! *Note: When Sony Batteries are out of stock we may substitute Renata, Eveready or other comparable quality batteries.