The 361, or SR721W, is a rare Silver-Oxide cell normally used in watches, with a shelf life of 5+ years. Other applications may include calculators, film cameras, medical instruments, cash registers, or FA instruments (Measuring Instruments, Onboard Microcomputers, Sensors).High Drain batteries are for applications with a continuous, low power consumption and occasional high peaks: Analog and digital watches with extra functions (backlight, alarm), pocket calculators, electronic games, cameras, etc. This is in comparison to low drain batteries, which are best used in devices that use a small amount of power over a long time: Analog watches, TV remotes, alarm clocks, etc.