SHIMANO ULTEGRA DI2 R8150 2x12V Braze-On Front Derailleur

From the new Ultegra 8050 electronic groupset, the SHIMANO Ultegra Di2 8150 2x12V braze-on front derailleur was designed to offer a wider range of gears, without compromising on shifting performance and whilst being as quiet as it is aerodynamic.
 

Fast and smooth chainring shifting is guaranteed in all conditions, even when you shift to the big chainring whilst out of the saddle.

Shimano's Synchronized Shift technology synchronises front shifting with any rear shift, allowing both derailleurs to work together efficiently.
With Semi-Synchronized Shift technology, it works the other way around: rear shifting is synchronised with any front shift, allowing an optimal gear ratio to be maintained.

At the same time, the Di2 auto-trim function will automatically and precisely centre the front derailleur around the chain, thus avoiding any chain rub when moving the chain across the cassette. That is how fast, precise and smooth your shifting can be.