The self timer. More useful than you think, especially on the M9. When in bulb mode you can hit the shutter button once to open the shutter and the LCD will count up the seconds (up to 240). Just hit the shutter button again to close the shutter. On the Ti M9 it's the only way to use bulb since it lacks a threaded cable release socket. The M7 and M8's LCD work the same way (going up to 999), but you'll need a locking cable release to keep the shutter button down. New on the M9 is the ability to disable it altogether to prevent accidental activation.