Features: This is an expansion kit designed for Pi, which provides 5 sets of 2x20 pinheaders, that means a handy- way to stack multiple different HATs together, and use them as a specific combination / project. Standard connectivity, directly pluggable OR through ribbon cable 5 sets of 2x20 pinheaders, connect multi HATs together ;Clear and descriptive pin labels for easy use USB external power port, provides enough power supply for multi HATs Reserved jumper- pads on the bottom side, pin connections- are changeable by soldering, to avoid pin conflicts Note: make sure there are no any pin conflicts between the HATs you want to use together before connecting-. Specifications: Item: for 4b/3b GPIO Expansion Board with: 5 sets 2x20 pin headers Dimension: approx 183mm×65mm/7.2x2.56in Mounting hole size: approx 3mm Package Includes: 1PC Stack HAT 1PC Ribbon Cable 40PIN 1PC 2x20 male pinheader 1PC RPi Screws pack (4pcs) note: Note: is not included Due to the problems of lighting effects and shooting angles, there will be certain tolerances in the product, please understand. Please allow 0-2mm error due to manual measurment.