Lithium batteries come in many different variants, differing in cathode, electrolyte, and separator. They are available in various shapes and sizes to cover a wide range of applications. Due to their high voltage of 3 volts, high capacity, wide temperature range, and long shelf life due to low self-discharge, they find a broad spectrum of uses. The main applications for lithium button cells include car keys, watches, medical devices, toys, LED flashlights, and of course, any form of memory backup.