DFRobot IO Expansion Hat for Raspberry Pi 3/4/400 features detailed Pinout information and is specially developed for Raspberry Pi. It’s perfectly compatible with Pi 3, Pi 4, and Pi 400. All IO ports of Raspberry Pi are led out one by one. The hat provides 40PIN comparison silkscreens that contain detailed BCM code and WPI code information. This saves the trouble of frequently checking the pin comparison table when programming with Pi.