Length: Optical 4X2 This SPDIF/TOSLINK Digital Optical Audio 4x2 Matrix allows you to share 4 distinct audio inputs between 2 independent amplifiers or speakers. Providing convenient front push-button and remote control, the matrix switch allows every two input to be switched individually, meaning that every two different input sources can be shown on different output equipment, or a single source could be output to two, offering maximum flexibility.