Blackmagic 3G-SDI Arduino Shield is supplied with 4 stackable headers, including two 8 pin headers, a 10 pin, and a 6 pin header. Headers are bridging connectors used to mount your shield to the Arduino board, and because they are stackable you can attach other shields on top with additional components, such as control buttons, knobs and joysticks. The header layout supports mounting to Arduino boards with an R3 footprint, such as the Arduino UNO.