Remote shutter release cord (remote commander)
It is really a very useful and helpful gear for prevent vibration when taking photos under long exposures, close-ups (macro) or continuous shooting.
The shutter release button of this remote cord can be pressed halfway for auto-focus and exposure metering. And, a shutter release button lock is available for long exposures shooting and continuous shooting helpfully.

Compatible with:
Canon EOS 7D, 50D, 40D, 30D, 5D, 20D, 10D, 5D Mark II, 1D Mark IV, 1Ds Mark III, 1D Mark III, 1D Mark II