Ruby or Sapphire tipped 3D Printer nozzles made by Olsson Ruby or 3D Solex lets you print spools and spools of abrasive materials without any degradation to your nozzles while keeping the superior thermal conductivity of brass nozzles vs. traditional hardened steel nozzles.  The finest nozzles you can buy to print any material your printer can handle.  Please check individual compatibility for each nozzle.