I think this is a later example of a chainstay mounting SunTour 888 Wide derailleur - probably manufactured by SunTour themselves (early versions were manufactured by a company called Iwai). This example has very similar branding to that on my ‘5th style’ example of the SunTour 888 Wide.
The underlying design remains a version of any number of French designs from the 1930’s (see the Super Champion/Osgear Grand Sport) . This Suntour is, however, a well executed example of the genre.
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