Review on Expansion Connector Raspberry Pi Pinheaders by Yung Kitamura

This board is great for both testing and deployment. While it is common to place HATs on top of each other and certainly to save space, this makes connecting external components such as sensors and antennas more difficult as the pins and connectors on the bottom HAT can become blocked by the HAT above. For example, imagine you've safely stacked 5 HATs with supports on the Pi - only to find that you need to reinstall the camera cable. Now you need to dismantle all 5 hats. Ouch! I hope you don't bend the pins in your frustration! What makes this board better than Pimoroni's pHat Stack is that it has a pass-through (through) header for the Raspberry Pi. This means you can mount the Pi directly to the board WITHOUT a bulky reduced voltage ribbon cable. Pi will be UNDER the board. If you need more space, just use the stack connector. This board also has its own micro USB connector!