"viTTL/ETTL High Speed Sync up to 1/8000th Nikon Compatible 1,500' Range NO Line of Sight NO Sunlight Interference NO Cables NO Programming or PC needed PX Transmitter The PX Transmitter is the core of the most advanced wireless flash system in the world. To take advantage of iTTL/ETTL and High Speed Sync, all while avoiding the drawbacks of line of sight, short range and sunlight interference, you'll need a PX Transmitter to control your remote flashes. One transmitter will allow you to control as many flashes as you want. The system is very easy to setup. Simply place the Transmitter on top of your master flash, commander or on-camera commander, attach your Receivers and you're good to go. PX Receiver For every off-camera or remote flash you'll use, you will need a PX Receiver. Although the PX Receivers and Transmitters are compatible with both Canon and Nikon, each Receiver comes with a mounting bracket that is specific to either Canon or Nikon flashes. Out of the box, the system is configured for Canon with menu options for configuring with Nikon, Nissin or Quantum gear"