The nominal voltage of alkaline LR/66LR626 batteries is 1.5 volts, and it lowers to 1.0 volts pretty quickly over time.However, most manufacturers now offer SR626 batteries (multi-drain) that may be used in keychain LED torches, thermometers, analog watches, both digital and toys, and other devices.
Furthermore, such batteries hold a higher capacity, allowing for a significantly longer operation duration for several devices with just one battery replacement. This remains rather stable when the batteries are discharged.
Silver Oxide 1.55 Volts Energizer 377-376 Watch Battery (SR626SW).Energizer 377/376 SR626SW SR66 Watch Battery.Product descriptions as SR626SW battery equivalent.Specifications and Features of SR626SW and LR626 Batteries.Safety Concerns with SR626SW and LR626 Batteries.