You will notice that with some of our boards you can choose: “Arduino Headers option”. We also have “Expansion headers”. Some of our customers are not sure if they need it or not. Let us clarify this today.
In short:
- If you are going to use only USB or JST/Pixhawk interface, you don’t need any headers.
- If you want to add a Shield for Second XBee socket, LiPo Battery Shield or Shield for Septentrio Native Ethernet, we recommend using the Expansion Headers.
- If you want to stack your ArduSimple onto an Arduino, an STM32, a Raspberry Pi, or your own PCB, we recommend choosing the Arduino Headers.
In long:
The Arduino headers are this plastic and metal receptacles that can be connected on the holes that the ArduSimple boards have at their edges. A picture will help you understand:

Below you will find an example of use of the Arduino Headers. Note that there is a board under the ArduSimple board, and you can also stack another expansion board above.

If you are not planning to stack your board onto an Arduino, Raspberry Pi, or similar, you will be ok with the Expansion Headers, you will find an example below. Note that there is no board under the GPS receiver board.

If you are not planning to stack your board onto an Arduino, Raspberry Pi, or similar, you will be ok with the Expansion Headers, you will find an example below. Note that there is no board under the GPS receiver board.