RAK2287 /RAK5146 Pi is a converter board with a Raspberry Pi form factor that enables the RAK2287 LPWAN concentrator module to be mounted on the top of the Raspberry Pi.
It integrates one (1) 40-pin female Pi HAT connector and one (1) PCIe connector to connect the module to the Raspberry Pi that is both compatible with the Raspberry Pi 3 Model B+/Raspberry 4 edition.
Raspberry Pi form factor with a 40-pin compatible header.
Compatible with the Raspberry Pi 3 Model B+/Raspberry 4 edition.
PCIe connector on board
1x RAK2287(RAK5146) Pi HAT converter board
RAK2287 Pi HAT
Dimensions: 65mm x 55mm x 18mm (±2mm)
Here is the link you want to buy a RAK2287 OR RAK5146