From the manufacturer's official website:

The new Centaur™ rear derailleur is distinguished by the carbon outer parallelogram link which marks it out as a component for competitions, and forcefully underlines its positioning in the top of the range of products for racing bikes. Alongside this the materials of the highest quality and refined design and manufacturing make this product a benchmark component.

Short cage: Upper to lower pulley-axle: 55 mm - composite outer plate.
Nominal weight: 227 g.

Medium cage: Upper to lower pulley-axle: 72,5 mm - composite outer plate.
Nominal weight: 232 g.

For more information, please visit this product's webpage.