A Schild – AS Calibre 1717 – Part No. 301 Regulator for flat hairspring (NOS) Related posts: A Schild – AS Calibre 1700 – Part No. 301 Regulator for flat hairspring (NOS) A Schild – AS Calibre 1916 – Part No. 301 Regulator for flat hairspring (NOS) A Schild – AS Calibre 1985 – Part No. 301 Regulator for flat hairspring (NOS)