Shimano ultegra fc6800 11sp double chainringsgenuine shimano replacement part for use with shimano ultegra fc 6800 11spd double chainsetcan also use the 39t inner chainring from the shimano dura ace fc 9000 this is a b match which indicates that the parts are usable but differ in materials appearance finish size etc speicficationsmaterial aluminumteeth 34t 36t 39t 46t 50t 52t 53tbolt pattern 4 boltchainring bcd 110mmchain compatibility 11 speeddoublea 2 year warranty is off