24 x channel analogue "Audiowire"expansion unit for the MOTU PCI424 card.
All in nice condition
The 24I/O is a single-space, rack mountable chassis with gold-plated analog audio connectors on its rear panel and level meters on the front. The rear panel has 24 gold-plated, balanced +4dB TRS analog inputs and outputs with 24-bit A/D converters.
Here's the manual >MOTU<