Apogee Big Ben Studio Clock, AES, S/PDIF, Optical I/O - Word Clock/Video In - 6 Word Clock Outs Optional X-Video expansion card to provide master video sync generator, Realtime format conversion between all digital formats, Direct Digital Synthesis (DDS) using Apogee´s C777 Clock Technology up to 192kHz, Adaptive Loop Filtering (ALF) to optimize clock performance and minimize jitter, Three stage Termination Sensing for each word clock output. 19", 1RU.