A work of art that slices through the wind, the Vision Metron rear derailleur delivers precise performance and unmatched aerodynamics. Crafted with aluminum and carbon fiber, the Metron rear derailleur sets the standard for time trials and triathlons. An aluminum B-knuckle provides strength, while an engineered plastic P-knuckle, carbon fiber links and inner and outer cages reduce weight and give it an unprecedented aerodynamic advantage. Vision completes the Metron rear derailleur with an 11-tooth upper and an energy-saving 15-tooth lower composite pulley. The Metron rear derailleur is compatible with Vision Metron and Shimano 10-speed drivetrains and can accept up to a 28-tooth cassette.