These are extruder nozzles which are suitable for the newer MK10 style print heads found on the newer Creator Dual Head, Creator X, Creator Pro, Inventor, Finder, Guider Guider II and Dreamer 3D Printers. These are 9mm wide and are NOT interchangeable with the older Mk9 version found on early Flashforge Creator 3D Printers or the Guider I