Simply slide the AC3 ZoneController into the shoe of an on-camera PocketWizard MiniTT1 or FlexTT5 and control three or more remote Canon Speedlites mounted with FlexTT5 transcievers. Three zones, marked A, B and C, correspond to Zone Switch settings on the receiving FlexTT5 units. Each zone has a Mode Switch that enables manual or automatic flash control or switching off a flash completely. Clearly marked dials allow increasing or decreasing the power of each flash in 1/3-stop increments over a six-stop range. Remote flashes need only to be turned ON and set to E-TTL and the correspnoding zone set on the FlexTT5 you wish to control. Photographers can switch back and forth between auto and manual flash control and use both for the same shot, all right from the camera's position.