A PCIe Gen4 x16 FMC+ Module is a high-speed FPGA mezzanine card designed around the ANSI/VITA 57.4 FMC+ (FPGA Mezzanine Card Plus) standard.
Instead of adding specialized analog or RF components, this module acts as a hardware bridge: it routes 16 multi-gigabit transceivers directly from an FPGA carrier board to a physical PCI Express x16 connector or cable assembly, allowing FPGA evaluation boards to operate as a standard PCIe Gen4 Root Complex or Endpoint device.
Please find the detailed product information here:
PCIe Gen4 x16 FMC+ Module