The Echo Express SEL Thunderbolt 3 to Low-Profile PCIe Card Expansion System from Sonnet provides a PCIe 3.0 x8 slot for Thunderbolt 3-equipped notebooks, SFF desktop systems, and other computers without a PCIe slot. The Echo Express SEL supports low-profile PCIe cards with a length of up to 6.6″, such as audio interface, SAS or SATA HBA, 16Gb or 8Gb Fibre Channel, 10Gb Ethernet, or RAID controller PCIe cards, which operate over the Thunderbolt connection. There’s also an integrated variable-speed fan for cooling your PCI card and the SE’s internal components.