The PocketWizard FlexTT5 Transceiver Radio Slave is part of an ultra-versatile radio slave system, and is dedicated specifically to the Nikon i-TTL flash control system. It simply slides directly into the camera's hot shoe, and there are no special settings to make or modes to call up. Use the camera, on-camera flash, or flash commander controls for flash compensation, zone and ratio control. It supports single or multiple dedicated flash units.The FlexTT5 is the ideal addition to any Nikon i-TTL flash system. Since this system works on digital radio technology, it can support i-TTL operation around corners, out-of-sight, or in bright sunlight.The FlexTT5 is a "Transceiver", meaning it can be used either as a transmitter placed into the camera's hot shoe, in combination with another FlexTT5 unit on the flash end, or as a receiver, with a MiniTT1 transmitter-only unit placed on the camera's hot shoe.