Shimano Dura-Ace Di2 R9250 2x12 34-50 Groupset W/ Disc BrakeThe Shimano Dura-Ace Di2 R9250 2x12 34-50 Groupset with Disc Brake is a top-of-the-line electronic shifting groupset designed for road cyclists who demand the best in terms of performance and reliability. The groupset includes both front and rear derailleurs, shifters, brakes, crankset, ca..