The Allen & Heath AH4131 Sys-Link Expander Option for MixWizard is a single expansion cable with a pair of 37-pin D-type connections for audio input and output. The Sys-Link Option combines 2 Allen & Heath MixWizard consoles for double the channel count. The consoles are linked with 37-pin D-sub cables (not included) and establishes Master/Slave operation for double the inputs and outputs while monitoring on the Master console's monitoring section.