M5Stack CoreInk Proto Base is a DIY expansion kit suitable for CoreInk master control. The IO bus on the CoreInk main control leads out to the PROTO board through the lower PIN when stacking the expansion board. This expansion kit also contains a variety of expansion ports that can be soldered to the PROTO board and adds standard specifications to the circuit design. The expansion ports include the HY2.0-4P female terminal, 3.96 male/female terminal, and DC power terminal. The CoreInk Proto Base features a LEGO compatible hole design on the corners and a hook hole on the back. This allows the finished DIY product to be easily embedded into a variety of structures. Typical applications include experimental circuit and DIY function expansion.