These headers are made to work with the Arduino Main Boards, Arduino Pro, and the Arduino Mega. They are the perfect height for clearing the USB-B connector and great for stacking multiple shields. This kit includes 4 headers (2 x 8-pin and 2 x 6-pin), enough to connect a shield to an Arduino Main Board.
Note: These kit comes with 8-pin Headers and not with 10-pin Headers. 10 Pin headers are needed for boards with Arduino R3 architecture which include the OREF, SCL, and SDA pins.
Image Credit: Sparkfun