This 20 pin header fits into the holes at the edge of the PSoCxPIM1 boards. They are convenient for attaching test probes, plugging into sockets or otherwise connecting to the rest of your system. You will need two for each Powerfulboard - one for each side. We offer them here as a convenience. You can also order them directly from Digi-key using P/N: S1211EC-40-ND. You snap these 40 pin headers into two.