This remote switch come with a 2.6' (80cm) cord to prevent camera shake for super telephoto shots, macrophotography & bulb exposures. The remote switch works just like a shutter button, enabling halfway or complete pressing. It also has a shutter-release lock. Its quick-lock plug connects to the EOS-3's remote control socket. Compatibility: EOS-1D Mark IV Body EOS 5D Mark III EF 24-105mm f/4L IS USM Lens Kit EOS-1 Ds Mark II EOS 1D Mark II N EOS 6D Body Refurbished EOS-1D EOS D60 EOS 40D with EF 28-135IS Refurbished EOS 7D EF 28-135mm IS Lens Kit EOS 40D Refurbished (Body) EOS 7D Body EOS 5D Mark III Body Refurbished EOS-1D Mark IV Body Refurbished EOS-1 Ds EOS 20 Da EOS 50D Body Refurbished EOS 30D EOS 6D Body EOS 5D EOS 6D EF 24-105mm f/4L IS USM Lens Kit EOS 20D EOS-1D Mark III EOS 7D Body Refurbished EOS 10D EOS 7D EF-S 18-135mm IS Lens Kit EOS 5D Mark III Body EOS D30 EOS-1 Ds Mark III EOS 5D Mark III EF 24-70mm f/4L IS USM Lens Kit EOS 40D EOS 50D (Body) EOS-1D X Body Refurbished EOS-1D X Body EOS-1D MARK II EOS 3 EOS 30D with EF-S 18-55 Lens Refurbished EOS 30D Refurbished (Body) EOS 50D EF 28-135mm IS Lens Kit