5mm Yellow Gold 18k PlatedSnake Chain 46cm "Air NK" Presumably by Harringbone.!!

5mm (air NK) 46cm 18k Plated over Silver Snake Chains ×2 Pre-owned gold chains.!! They were purchased in the late 1990s.The maker is presumed to be Harringbone Jewelry.But they were not authenticated.!! Lots of plated gold content ×2 chains.!! Words inscribed "Air NK"...Recently conducted the magnet test and absolutely no movement only the Clasp Moved under high resolution magnification.!!