When prototyping or designing your own shield for the Arduino UNO, you will need these single inline headers. This kit includes 4 headers (1x 10-pin,2 x 8-pin, and 1 x 6-pin), enough to connect a shield to an Arduino Main Board. These are the same headers we use in our tutorials and with our own shields. They all have 2.54mm spacing between pins and they are the perfect height for clearing the USB-B connector and great for stacking multiple shields