With the Speedlite 550EX and the Speedlite Transmitter ST-E2, it is now possible to use multiple Speedlites under full E-TTL control and without the need for any interconnecting wires. Developed in conjunction with the Speedlite 550EX and the EOS-3 camera, this master control device for a wireless Speedlite flash system meets professional and advanced amateur standards. Its dedicated transmitter controls up to 3 Canon 550EX Speedlites as slave units 33ft. away outdoors and 49.5ft. away indoors. It is mounted as a clip-on with shoe lock lever and locking pin. Models: 550ex, 420ex off camera. Battery not included.
Features
Compatible Type A EOS cameras (E- TTL, autoflash); Type B EOS cameras (Manual flash) and the Powershot-G9 digital camera
Dedicated clip-on transmitter for E-TTL/E-TTL II wireless flash system