1. Based on the 40-pin GPIO interface, it is suitable for a series of motherboards. 2. It uses relays, allowing the connection of loads: less than AC 250V, 5A or less than DC 30V, 5A. 3. It is equipped with optocoupler isolation to avoid interference from high-voltage circuits. 4. It comes with a relay indicator light for easy viewing of the relay's working status. 5. It comes with a relay jumper cap for easy switching to other pins for control. 6. Product Name: Relay Expansion Board 7. Load: Less than AC 250V, 5A or less than DC 30V, 5A 8. Applicable Models: Suitable for 4B/3B/3B+, Nano 9. Product Size: 65.15×56.21 mm 10. Color: Blue 11. Material: PCB + Metal 12. Package Contents: - One 3-channel relay board - One pack of screws 13. Only the above items are included in the package, and no other products are included. 14. Note: Light reflection and different monitors may cause slight differences between the color of the item and the actual object. The allowable measurement error is plus or minus 1 - 3 cm.