This bush, called knurled wheel, is a replacement compatible with Ultimaker printers. this is a knurled toothed pulley that allows the filament to flow smoothly during printing. You need to hook the wire to the bush so that it can move to the bowden. After many prints the bush can get dirty with small filament fragments. In this case it can be cleaned with compressed air or with a brush.
The item that you can get for certain features differ from the one shown in the photo, depending on the production lot. However, the functionality is retained. The description of this item has been provided by automatic translation. If you have any questions, please do not hesitate to contact us.