According to Edith Reiter's 2014 book, this instrument was completed on 10 April 1926 and originally sold to a buyer in an unknown location.
Howe & Hurd (2004) describe heckelphone #3970 as a model 36i, tuned at A=440;
As of 2004, heckelphone #3970 has been reported to be located in Detroit (MI), USA, owned by Victoria Alexander. Previously, it was part of the instrument collection of jazz clarinetist Curtis (Curt) Guckert of Dallas (TX), USA. The earlier history of heckelphone #3970 remains unclear.