According to Edith Reiter's 2014 book, this instrument was completed on 26 November 1912 sold to a customer in an unknown location.
The model of heckelphone #3423 is unknown, but it is plausible to assume that it is a model 36b or 36i.
As of 2020, this instrument is part of the collection of the Museo Internazionale e Biblioteca della Musica in Bologna, Italy.
The history of heckelphone #3423 remains mostly unclear.
Pictues of and detailed information about heckelphone #3423 can be found here.