Shimano SLX M660 10 SPD ChainringShimano SLX M660 10-Speed chainrings are a direct replacement for your 10-Speed Shimano Dyna-Sys chainrings. The inner ring features a 64mm BCD and the middle and outer rings are 104mm BCD. All three rings have a 4 bolt pattern.Features10 Speed DynaSys32T 104BCD Middle Chainring | Shimano SLX M660 10 SPD Chainring 32T, B-Type