My rough translations of the photo captions, clockwise from top left are:

• SunTour 7
• SunTour VX
• SunTour VX
• SunTour 7 GT

I think that more complete labels might be:

• SunTour Seven (1900)
• SunTour Vx GT (2400)
• SunTour Vx S (2500)
• SunTour Seven GT (2000)

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: SunTour
• Derailleurs: SunTour Vx S (2500), SunTour Vx GT, SunTour Seven (1900), SunTour Seven GT (2000)