Yongnuo 2.4GHz Wireless Remote Flash Trigger and Two Receiver For Canon EOS 550D/500D/450D/7D/50D/40D/30D Powershot G11/G10/G12 Canon 580EX II 270EX II Using global free 2.4GHz channel and FSK modulation system, and there's 15 selectabh frequency channels. Flash sync speed is up to 1/250s; Support the flashgun wake-up function; you'll never miss any shot opportunity. (Wake up can only used in TTL Compatible flash). Fire the flashgun through hot shoe part and fire the studio light through PC socket. Supports to control multiple flashguns and studio lights at same time Supports to control multiple cameras to take shots at the same time; Maximum operating distance is up to 100 meters.