To convert standard XTR-980 and XT-780 shifter units to i-spec integration with corresponding brake levers
SH-53624 and SH-53625: are compatible with 2011-13 Shimano brake levers (M988/985/820/785/675/666/640/596) and are not compatible with 2014 B-type brake levers
B-type i-spec model is compatible with 2014 B-type Shimano brakes and can be used with 2011 i-spec compatible Shimano brake levers with the special nut (included)