The ARRI KC 156-S connects the Ethernet socket (Lemo 10 pin) on the ALEXA or ALEXA XT family of cameras to the EXT socket on another ALEXA and ALEXA XT camera in order to synchronize the settings of one camera to another for 3D and other applications. Can be used concurrently with the EXT to EXT Cable (K2.72032.0), which will provide precise sensor and HD output synchronization.