Works beautifully with popular boards like Arduino and Raspberry Pi. Tip: For this low price, and due to the long delivery time understandably better order two or three modules, because - just like me - sometimes a defective (eg turned rusted, see photo) relay can be there. Maybe the container ship from China had rough seas, so that the parts have become moist but ;-) A complaint is not worth it at that price in my opinion. For the "rust bucket" there's a star deduction.