NX 1x Rear Derailleur Dura-Ace Di2 Most later Shimano derailleurs use

Most later Shimano derailleurs use an 11T pulley and this item would not fit those derailleurs

the B17 Short

it's too big

With a comfortable

designed for use with carbon fiber rims

NX 1x Rear Derailleur Dura-Ace Di2 Most later Shimano derailleurs useThe SRAM NX X HORIZON rear derailleur provides the same smooth, reliable shifting action as XX1 from the larger upper pulley offset to the 12 tooth X SYNC pulley wheels. By eliminating unwanted chain movement, X HORIZON shifts faster, puts an end to ghost shifting and reduces shift force and chain slap. And with CAGE LOCK technology, wheel removal and installation are easier than ever.