HP 684577-001 PCI card retainer is a workstation component identified as SPS-Assy PCI Retainer ENV. It is intended to retain a PCI card in an HP workstation, serving as a replacement part for the relevant assembly.
The distributor lists it for the HP Z840 workstation 1GH56US. Its part number makes it identifiable as the specific retainer assembly when servicing that system. This description covers the listed PCI retainer; it does not specify dimensions, materials or package contents.