Description: Material: Stainless steel For Reprap 3D Printer Extruder End 4.1mm Heating end thread: M6 Compatible with v6 4.1mm hotend Thread diameter: 6mm Inner hole: 4.1mm White Teflon tube : 2mm Outside diameter: 4mm Package Includes: 5 Pieces All-Metal Throat with Teflon tube ( for 4.1mm Filament )