HP Thunderbolt 3 PCIe 2-port I/O Card with Cable / L33676-001 / L22981-001 192545159586 | eBay
HP Thunderbolt 3 PCIe 2-Port I/O Card on Z840 - HP Support Community - 8298816
HP Thunderbolt 3 PCIe 2-Port I/O Card on Z840 - HP Support Community - 8298816
L33676-001-HIGH P HP DUAL PORT TBT3 ADD IN CARD - THUNDERBOLT 3 AIC PCI-E X4 ( 2 ) TWO DISPLAYPORTS DP ( 2 ) TWO USB TYPE C ( KIT PN: 3UU05AA / 3UU05AT )
Hacking Thunderbolt Part 1: Why that add-in card doesn't work properly in your unsupported PC – Matt's Tech Pages