The new Chorus HO (Hydrualic Optimized) rear derailleur offers the level of quality of the Record series in an affordable package The new Chorus HO (Hydrualic Optimized) rear derailleur offers the level of quality of the Record series in an affordable package Carbon main body with aluminum reinforced carbon cage Pulleys made of a vibration resistant material for smooth function Ultra-ShiftÌÎÌ_ÌÎ_ÌÎÌ__ÌÎÌ_ÌÎ_ÌÎå«Ì´å exclusive geometry parallelogram