Features PIN DETECTION: Based on the 40PIN design, it can be inserted directly, all GPIO function pins can be drawn out to test whether all pin functions are normal. APPLICABLE MODEL: Can be used to test whether all pins of the equipment are in good condition, suitable for 3B 4B CM4 models, and has good compatibility. STANDARD HOLES: The expansion board has standard hole location and terminal block, with demonstration code and user guide, easy to use. EXCELLENT CHIP: The expansion board module is equipped with ADC chip, which can read ADC signals and send DAC signals. TERMINAL PORT: On board industrial terminal female port, with interface definition sticker, easy to identify, suitable for board beginners. Specification: Item Type: Sensor Expansion Board Model: PI ALL GPIO TEST BOARD(B) Material: PCB Application: For 4B 3B CM4 Package List:1 x Expansion Board4 x Screws2 x Nuts1 x QR Code User Manual Package List 1 x Expansion Board 4 x Screws 2 x Nuts 1 x QR Code User Manual