Yongnuo YN RF-603 C3 Wireless Flash Trigger Shutter Release Remote Control For Canon C3 for 1D 5D II 7D 50D 40D 30D 20D Suitable for Cameras: Canon EOS 50D, 40D, 30D, 20D, 10D, 7D, 5D, 5DII, 1D. Works as a wireless shutter release control:Auto focus, continuous shooting, long exposure, half-way pressing, full-way pressing. works as a wireless flash trigger and receiver:The unit automatically detects the mode it should work in. You have the full flexibility out of your gear. Supports wake up function and the "Wake up" function is only supported for flashes which have a sleep mode. Using a PC Sync cable the transmitter can wirelessly and synchronously trigger your studio strobes.