SHIMANO Di2 electronic shifting lets you change from the big to small chainrings, or vice versa, whenever you like while minimizing the risk of a dropped chain. Similarly, you can perform rear shifts without the need to trim the front derailleur to avoid chain rub. Full- and semi-synchronized shifting functions can be selected using the E-TUBE app. With digitally accurate electronic shifts and coordinated communication between shifters and derailleurs, the new SHIMANO 105 front derailleur offers the best shifting you've ever experienced.