SR521 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:
SR521 batteries can be used to replace the following: SR521SW, SR63, SR521, SB-AC/DC, 280-59, JA, V379, D379, 618, GP379, S521E, 379, LR521, AG0, 379A, 379X, AG0, AG-0, 521A, UC379, SR418SW, SB-AC, 379LD, E379. All have dimensions of 5.8 mm diameter 2.15 mm height, and a capacity of 16 mAh.