This morse key was built in the Swiss telegraph factory Gustav Adolf Hasler (1880 to 1909). It is a special model, with 2 independent contacts (1x contact, 1x changeover or duplex) which was mainly used by the Swiss railway companies.
My key was used by the Rhaetian Railway Company and, after my licensing, became my only key for more than a year (approx. 500 QSOs). At the beginning of 1976 a Heathkit HD-1410 was added and later different paddles together with the ingenious Logikey K-5.