The AMS Hub is used to expand the number of AMS connected to Bambu X1/P1 series printers from 1 AMS unit (4 channels) to a maximum of 4 AMS units (16 channels) to improve the refueling speed across your multiple AMS units and support the redundancy of a buffered signal. *The Bambu Lab AMS Hub includes the necessary accessories to connect 2x AMS units to the printer. If you wish to add more AMS units, you need to order additional Bus cable and PTFE Tube. To use 4x AMS units, you need to order additional 2x Bus cable (6pin) and 2x 2m PTFE Tube.