To celebrate the 25th anniversary of the first Dura-Ace groupset, Shimano released a special commemorative groupset including this 9 speed derailleur. Note the subtle golden ‘25’ written to the left of the Dura-Ace logo.

Other differences were a titanium hanger bolt and cable clamp bolt, stainless steel pivot points and (for some reason) black pulleys with white writing on them.

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1. •Brand: Shimano
   

2. •My category: Shimano - the Dura-Ace story
   

3. •Country: Japan
   

4. •Date of introduction: 1998
   

5. •Date of this example: 1998? (no two letter date code)
   

6. •Model no: 7700 SS
   

7. •Weight: 189g
   

8. •Maximum cog: 27 teeth
   

9. •Total capacity: 29 teeth
   

10. •Pulley centre to centre: 49mm
    

11. •Index compatibility: 9 speed
    

12. •Chain width: 3/32”
    

13. •Logic: top normal
    

14. •Pivots: two sprung pivots
    

15. •Material: aluminium
    

0251/I