The EKW C-35 was a 1930s Swiss two-seat reconnaissance biplane aircraft built by the Swiss Federal Construction Works (Eidgenössische Konstruktions Werkstätte, K+W), Thun.
The first aircraft was delivered to the Swiss Air Force in May 1937, and all had been delivered by the end of 1938. To supplement the aircraft in-service a further eight aircraft were built between 1941 and 1942 from spares. The aircraft were removed from front-line service in 1943 when replaced by the F&W C-3603 and transferred to night-flying units. The aircraft was withdrawn from service in 1954.
Info: Wikipedia
http://en.wikipedia.org/wiki/EKW_C-35
Profile: Spafi
http://www.spafi.org/resources/category/19