Remote switch is useful to prevent camera shake for super telephoto shots, macrophotography, and bulb exposures. The RS-80N3 remote switch works just like a shutter button, enabling halfway or complete pressing. It also has a shutter-release lock.Compatible Products: EOS 10D,EOS 1D ,Mark II N,EOS 1V,EOS 20D,EOS 20Da,EOS 3,EOS 30D,EOS 40D,EOS 50D,EOS 5D,EOS D30,EOS D60,EOS-1D,EOS-1D MARK II,EOS-1D Mark III,EOS-1Ds,EOS-1Ds MARK II,EOS-1Ds Mark III