MakerGear V4 Hot End Replacement Barrel (Heatbreak)
Important note: a new nozzle is recommend when installing a new barrel. Here is what MakerGear says:
"Once a new nozzle has been installed onto a barrel, do not install that same nozzle onto a different barrel or leakage may occur. As you install a new nozzle onto a barrel, a small amount of material is removed from the nozzle to create a custom fit. This makes the nozzle incompatible with any other barrel due to the slight variations in tolerances among different barrels."