Customize menubar for different states

If on, it allows completely different menubar icons and details to be shown for when your battery is draining, charging or charged. This lets you do things like adding a time until drained to your menubar while your battery is draining, but hide it while your Mac is plugged into main power.

Apple Bluetooth keyboards, mice and trackpads

iStat Menus can display the battery level for most Apple wireless keyboards, mice and trackpads. These are shown in the battery drop-down menu.