According to Edith Reiter's 2014 book this instrument was completed on 24 March 1957 and originally sold to a buyer in the Netherlands.
Howe & Hurd (2004) describe heckelphone #4935 as a model 36 cons; it has been equipped with an extra touch for low A.
As of 2004, heckelphone #4935 is located in Hilversum, Netherlands, and owned by the Radio Filharmonisch Orchester Hilversum, played by oboist Frank van Koten.
The history of heckelphone #4935 remains largely unclear.