The complete extrusion screw barrel components include 1 screw and 1 barrel. And the twin screw barrel includes 2 screws and 1 barrel.

The quotation from HUACHEN SCREW includes a complete set of screw and barrel. It is generally not recommended to order screw and barrel separately.

First, the barrel screw is a large custom machined parts for the extruder. A complete set of screw barrel could perfectly match the gap between barrel and screw, it is good for plastic materials.

Then, a complete set screw and barrel could provide the same wear and tear degree on both screw and barrel.