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Through Ebay I have now acquired two Sunpak DX modules that came attached to flash units.
[For anyone not familiar with the Sunpak DX system of the late film era, these modules plug in semi-permanently to the bottom of the flash unit, and provide the foot. There was a different module for compatibility with each major camera brand. Many users of the DX flash units (and Ebay sellers) never even realise the module is detachable.]
My modules are both Pentax compatible (code PT) but one is marked "PT-1D" and the other is "PT-2D". The former also gives a list of 1980s Pentax cameras it is for, while the latter simply says it is for Pentax cameras. Both say it can also be used generically (except Sony I guess).
Does anyone know the functional difference between these? One came with a 36DX unit and the other with a G4500DX, but both manuals refer only to the PT-1D. The PT-2D does work with both though, maybe it is improved somehow.