Bower RCRC3  3-In-1 Advanced Wireless Remote and Trigger for Canon EOS 7D, 5D Mark II, 50D, 40D, 30D and 1D Mark IV (Black) Works well with studio strobes and speedlites Boasts four channels per receiver for up to 16 unique slots for studio strobes or flashes at one time Use as camera shutter release, strobe trigger or control your speedlite off-camera Includes one 23A 12V alkaline battery, two 1.5V AAA batteries, remote, trigger and cords Compatible with Canon EOS 7D, 5D Mark II, 50D, 40D, 30D, 1D Mark IV Digital SLR Cameras