Shimano 105 5800 double 11sp band on front mechwide link design 105 double front derailleur for increased rigidity and improved shifting response features for use with 105 st 5800 or ultegra st 6800 shifters only for optimum shifting performance wide inner link increased rigidity and takes front shifting performance to a new level especially under heavy load for 11 speed drivetrains long pull arm for light action spring reduces effort required to actuate shifts support bolt provides added stab