Motor parts: The external synchronizer (Dual Hall)
This is dual Hall needle positioner, and the design is perfect, and It matches the sewing machine head very well. The plug can match the 4 core interface very well. Pls kindly see the below diagram: Mark in red circle.
This 4 core interface is for needle positioner plug. They connect so that the needle position function works.
Two different connection rod (M5 and M6) match diffrent machine head. It give the buyer more choice to reach their purpose. The below picture is the detail.