sonnet echo iii desktop a 3-slot desktop thunderbolt 3 to pcie card expansion system sonnet technologies connect three full-length pcie cards to computers with thunderbolt 3 ports. for creative pros using the latest portable, mini desktop and all-in-one computers in their workflows, onboard processing power alone is not enough to get the job done. while these computers include high-performance thunderbolt 3 ports to support peripherals, what they lack is pcie expansion slots to install specialty cards that add needed video and audio inputs, transcode data, and connect to high-speed shared storage and networks. sonnet has a solution, the echo iii desktop—a professional thunderbolt 3 to pcie card expansion system that enables you to connect three (up to) full-length (12.28 inches long) pcie cards at the same time, via a single cable.