The predecessors of the Anycubic Mega Hub with ESD protection have all the same dimensions. The differences can be seen below.

The first version still contained the original connectors

I3 MEGA HUB-II distribution circuit board
Top	Bottom

The schematic diagram and pinout of the board can be downloaded from here:

• I3 MEGA HUB2 schematic diagram
• Pinout / Pin description of the connectors at the circuit board.

Specially for adding a cable chain to the printer, a further redesign of the circuit board (I3 MEGA HUB3) was made:

• ANYCUBIC I3 MEGA HUB3 redesign

The improvements are mainly that the connections for the X, Z (right) and E0-steppers (filament) were placed on the right side, making a single cable chain with all necessary wires for the steppers easier to realize. The wires for the left Z-axis are still placed on the left side, as these do not have to be running through the cable chain.