According to Edith Reiter's 2014 book, this instrument was completed on 11 February 1926 and originally sold to a buyer in an unknown location.
Howe & Hurd (2004) describe heckelphone #3951 as a model 36i, tuned at A=440; it appears to be one of the first instruments with the three-hole bell design, a perforated bottom plate and a central floor peg. In 2004, this heckelphone has been modified to a model 36 voll cons.
As of 2020, heckelphone #3951 has been reported to be located in Las Vegas (NV), USA, owned by collector Greg Smith. Previously, it was owned by Peter Hurd of Seattle (WA), USA; by collector and bass player Frederick R. (Eric) Selch, New York (NY); and by oboist and collector Richard Abel. It was sold at Sotheby's in New York (NY) in 1985. The earlier history of heckelphone #3951 remains unclear.