This tiny mod board can be used to add 2.5 Gigabit Ethernet to devices that have PCIe available internally. It can
for example be used to replace an existing 1 Gigabit PCIe NIC in embedded devices, upgrading them to 2.5 GbE connectivity.
The board is based on the cheap and well-supported RTL8125BG PCIe 2.5 GbE Ethernet controller.
This mod board is tiny enough to fit inside many small form factor devices. It can for example be installed inside the ARM64-based NanoPi R4S to upgrade it to 2.5 GbE.