Shimano slx fcm675 10 speed double chainringsride shimano and enjoy the benefits of their no compromise attitude shimano use the best materials for unrivalled performance the middle chainring is made of steelcomposite for more durability features10speed dyna sysdyna sys specific hg x 10 speed mountain drivetrain compatibilitya 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr products buyshimano componentsfrom chain reaction cycl