These headers are made to work with the Arduino Uno R3, Leonardo, and new Arduino boards going forward. They are the perfect height for clearing the USB-B connector and great for stacking multiple shields. This kit includes 4 headers (2 8-pin, 1 10-pin, 1 6-pin, and 2x3-pin), enough to connect a shield to an Arduino board. These are the same headers we use with our own shields.