West Australian Colonial 18ct yellow gold fob chain the T-bar is stamped 'A.O. KOPP' '18C' and with a 'Key' stamp - for Adolf Otto Kopp (working Fremantle 1891-1905), each chain link stamped '18' weight 60.7 grams. Reference: gold & Silversmithing in Western Australian by Dorothy Erickson, page 63