- Wireless flash controller for the Canon 420EX and 550EX and other Canon flashes
- Indoor transmission range of approximately 40 to 50 feet
- Outdoor transmission range of approximately 26 to 33 feet
- 1,500-transmission battery life
- Turns off after 90-second idle
The Canon ST-E2 Speedlite Transmitter is a dedicated E-TTL (II) wireless autoflash transmitter that can control an unlimited number of flashes with Canon Speedlites 420EX, 430EX, 430EXII, 550EX, 580EX and 580EX in two separate groups; A and B.