HKS was founded in 1973, this type of case by consulting the official catalogs had already been modified (1.5 mm thicker, bottom painted black (not chrome domed), winding crown cylindrical (not oval).
It remains a little mystery ... I opened the stopwatch and is well preserved.
The dial is absolutely unique and I had not ever seen one before.
We all know that these items are second-class compared to the wrist chronographs.
The container for watches is kindly offered by our friend Abel.
Heartfelt greetings to all.