Many people hardly noticed the Shimano XTR (M910) series derailleurs when they were released. Shimano designed them to look almost identical to the previous XTR (M900) series. Look more closely and you will see that most of the major parts have been changed. The parallelogram spring is no longer wrapped around a pivot at the p-knuckle. The inner parallelogram plate no longer incorporates a spring tension adjuster. Even the b-knuckle has been redesigned. The M910 uses Shimano's 'Advanced Light Action' design where the main spring runs across the diagonal of the parallelogram.
Mechanically the XTR (M910) was as different from the XTR (M900) as the Dura-Ace (7700) was from the Dura-Ace (7402). But whereas the two Dura-Ace models were styled to look radically different from each other, the two XTR models posed as identical twins.
This is a fine example of the 'mid length' pulley cage version of the Shimano XTR (M910).
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