Standard brass nozzles have fantastic heat-transfer properties but are affected by the material passing through them. Abrasive materials such as carbon-fiber composites wear at the nozzle diameter and shape of the tip. Filament can also harden on the outside of the nozzle changing the shape and disturbing your print and damaging your finish. This is especially noticeable with "messy" filaments such as PETG.

For abrasive filaments we recommend using The Olsson Ruby Nozzle and for cleaner prints with a sharp finish we recommend Olsson Precision Nozzles. Aside from their non-stick coating Olsson Precision Nozzles are hardened and can be used for occasional printing of exotic filaments. The High Temp version of The Olsson Ruby Nozzle combines the benefits of both. See our list of tested materials below.