Phottix Strato TTL Wireless Flash Trigger Set for Canon -  Transmitter and Receiver (PH89015) TTL flash trigger with EV adjustments (+/- 3 stops in 1/3 stops) Quick-change buttons and Backlit LCD to adjust EV level, mode, and channel High Speed Sync mode - 1/8000s Second Curtain Sync mode Wired and wireless shutter release functions