If you need one board to interface with another board, putting an FFC connector on your board is a pretty good idea. An FPC (Flexible Printed Circuit) is a custom flexible PCB, usually of dark ...

The Radxa Dual 2.5G Router HAT is an add-on board for single-board computers like the Raspberry Pi 5, and several other single-board computers from Radxa (and theoretically other companies as well).