All of the pictured portable electronic devices are powered by the same common affordable lithium CR2032 battery. The CR2032 battery is about the size of a nickle and provides five years of power for watches and calculators. Batteries can be swapped between devices in the event of battery failure. The CR2032 has a longer than average shelf life so spares will have plenty of voltage when needed. Device battery type is as important as function for making the grade at the chart table.
