Deep Engraving directly into "harderned" plastic die moulds. Typical steels are Stavax and P20. For fine detailed jobs that is impossible to machine by CNC machines where you have limitations from cutter diameters.The laser can produce sharp corners.
The sample photo shows letters 0.9mm high engraved 0.3mm deep on a internal diameter of 10mm. Detail is very clear, considering the small size