The Moving Cast Off Horn pushes the Loops down the Hook past the Latch. It also helps control the length or amount of Supplemental Thread that is in the purl or edge of the Stitch Loops. The Moving Cast Off Horn should be set so that the point of the Horn on its rearward travel captures the Supplemental Thread while the Hook is catching both the Needle and the Supplemental Thread.

The Horn must also be set far enough forward so that the Horn sheds the loops formed around it on its forward travel path. The Horn can also be adjusted laterally (right to left) to optimize its path and prevent contact or interference with the Hook.