These headers are made to work with the Arduino Main Board, 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 8-pin and 2 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.

Includes:

• 2x - 8-pin Arduino Stackable Headers
• 2x - 6-pin Arduino Stackable Headers