Yongnuo 1pc YN-622C-TX + 3pcs YN-622C E-TTL Wireless Flash Controller Wireless Flash Trigger Transceiver For Canon EOS 50D 60D 70D 7D 5D Mark II 5D Mark III 500D 550D 600D 650D 700D DSLR Flexible LCD menu control, supporting mixed use of the A/B/C three groups of flashes using E-TTL, manual or super sync flash mode, can be adjusted the exposure compensation or flash output of each group It supports setting different zoom of the three groups of flash, the remote-controlled distance can reach 100M, supporting seven wireless channels and A/B/C three groups Equipped with the AF-assist beam emitter. Supports USB firmware upgrade Shutter Sync: first curtain sync, second curtain sync and FP high-speed sync, the highest sync speed is 1/8000s Support wireless shutter release function