The only thing I am allowed to say regarding the 156 is that it was "very, very expensive and worth every penny"

The Scubapro spg and the 109 were bought by me in the day. The Mark V "type" first stage is one of a number of these I acquired in the day when Tekna shut down. They are 99% parts compatible copies of the Scubapro Mark V but had better chrome and a stainless steel turret bolt. This one was refitted with a cave seat and set for 126 psi IP.
James