The MSU (Material Switching Unit) is a multi-material upgrade based on the MMU2, with key improvements to improve reliability, price and compatibility.
needs to be relatively light (no full-size PC connectors)
part calibration with 5 or 6 different clearance options (horizontal hole compensation, filament expansion, and other factors mean that getting an accurate filament path is extremely set up dependent)
focus on reliability for this first version (high retractions might be needed because of a looser filament path but can be solved down the line)