"Aputure TTL cable is a special new tool for your speed light flash. By connecting your DSLR and your flash with the 3 meter cable, you can fire your flash off-camera for enhanced lighting effects. It also supports TTL flash exposure control and focus auxiliary light function. 1) TTL cable is a special new tool for your speed light flash. 2) Connecting your DSLR and the external flash with the 3 meter cable. 3) You can fire your flash off-camera for enhanced lighting effects. 4) Supports TTL flash exposure control and AF focus auxiliary light function. 5) Cable Length: 50cm 6) Extended Length: Approx 3m"