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

• New Skitter
• New Skitter
• New Skitter
• New Skitter

I think that the correct labels might be:

• SunTour Hero
• SunTour Echo
• SunTour New Skitter
• SunTour Echo

• Publisher: New Cycling
• Document: New Cycling May 1981 - '81 Derailleur Collection
• Date: May 1981
• Derailleur brands: SunTour
• Derailleurs: SunTour New Skitter, SunTour Hero, SunTour Echo