SR621 silver oxide (SR) and alkaline batteries (LR) are commonly used in watches, clocks, timers, calculators, laser pointers, toys, and LED "blinkies". Batteries that meet the IEC 60086-3 standards for watch batteries carry a "W" suffix. The functional differences between silver oxide and alkaline are:
SR621 batteries can be used to replace the following: SR621SW, SR60, SR621, SB-AG/DG, 280-34, T, V364, D364, 602, S621E, GP364, AG1, AG-1, 364, L621, LR621, SG1, LR60, LR620, SW621, GP164, 364X, 364A, AG1/364A, SB-AG, E364. All have dimensions of 6.8 mm diameter 2.15 mm height, and a capacity of 20 mAh.