Found! The beginning of the 15 μm thin wire thread (about 1/4 of a human hair), of which high-quality precision screen coverings are made at Haver & Boecker (click to enlarge)
Haver & Boecker OHG Oelde Die Drahtweberei wire weaving Institute of Mineral Processing Machines (IAM) processing technology raw materials recycling TU Bergakademie Freiberg mechanical engineering studies