This stainless steel heatbreak is already equipped with an internal PTFE tube. The heatbreak is compatible with the MK8 extruders and most Prusa 3D printers. The heatbreak has a length of 40mm.
NB! The heatbreak is made of thin-walled stainless steel. Too much force will tear the metal. Always use a counter wrench when tightening the nozzle, so that the force is not applied to the heatbreak.