The Pocket Wizard AC3 ZoneController allows you to control your flash set up directly from your camera's position. Simply add it to your on-camera MiniTT1Transmitter or FlexTT5 Transceiver and you instantly have three zones of flash control whether working in E-TTL II or Manual model. Put your flashes wherever you want without worrying about having to access them during a shoot. With the AC3 ZoneController, you are in total control of your flash.Three clearly labeled dials allow you to increase or decrease power to three zones of flash in 1/3-stop increments with a range of up to six stops. Three switches allow you to change zones between Manual, Auto (PowerTracking/E-TTL II) or OFF. Best of all, the design is simple with an intuitive interface. A firmware upgrade is now available for TT1 and TT5 via the Pocket Wizard website.