Featuring a hard-wearing aluminium build, this rear derailleur is engineered for toughness and reliability as you clock up the miles on your road bike. Campagnolo has also developed this model for constant precision, even on rough roads by positioning the spring between the upper body and the pivot to absorb vibrations and ensure the chain always rests properly on the sprockets. Another highlight is the pulley wheels on the 12 tooth derailleur cage allow your chain to move more smoothly for efficient shifting. The initial position of the rear derailleur can be adjusted to suit any cassette plus it offers easy wheel replacement by positioning the rear derailleur further back, making it easier to slide the wheel out and replace it. 12 Speed Rear Mech with  3D Embrace Technology The updated Chorus rear derailleur benefits from the same technology and design of top-end Campagnolo products, incorporating the sophistication and performances of the 12 speed Super Record and Record. With just a few changes in the materials used for its construction, like the external plate and derailleur cage in aluminium, the Chorus version produces exactly the same performance as the two more expensive groupsets with the addition of just a few extra grams. Chorus brings with it the same technology as the next level up, like the optimised trajectory on bigger cassettes and fantastic 3D Embrace technology. The latest evolution in Embrace technology not only keeps the rear derailleur vertically aligned in the perfect position for each sprocket, it now makes the upper pulley wheel advance perfectly in the direction the bike is advancing. 3D Embrace technology and 12 teeth pulley wheels make this rear derailleur suitable for all cassettes as the distance stays optimum on each individual sprocket, regardless of the cassette selected. Technologies: 3D Embrace Technology: The movement of the rear derailleur is designed to make the chain embrace more teeth per sprocket to guarantee maximum traction. Optimised Trajectory: Movement of the rear derailleur means that the upper pulley wheel on the cage is always constantly close to the sprocket in use. 12 Tooth Pulley Wheels: Perfect for cassettes that have a wide range of teeth. Optimised Return Spring: This guarantees constant chain tension regardless of road vibration. Suitable for use with the disc or rim brake groupsets. Manufacturer's Part Number: CPB115 Black Medium Cage