Based on for 40PIN design, It can be inserted directly after welding. Lead out all GPIO function pins to test whether all pins function well. As an TEST BOARD, Lead out all for 3B/4B/CM4 function pins to test whether all pins function well. As an expanding board, this module includes LED, basic function, You can get started easily. This is a simple expansion board, suitable for beginners of forRaspberry Pi. For 3B/4B and zero. Onboard ADDA chip, ADC signals can be read as sensor expansion boards, and signals can be sent out. Onboard industrial wiring terminal port, the terminal has interface definition stickers, Board more beautiful and practical. Note:Do not include for 4B, Please Buy alone. Colour:As Shown Material:Metal+Plastic Package Contents: 1 * expansion board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.