The evolution of the proven 1x specific X-Horizon design, the XX1 Eagle Rear Mech answers the need for greater range combined with the same smooth pedalling feel & consistent shifting. A new Type-3 Roller Bearing Clutch features a smoother torque curve for a quieter, more consistent operation, perfectly keeping the chain tensioned to prevent chain slap & dropping the chain. Large, 14 tooth lower pulley is the key to allowing the 10-50T cassette of the XX1 Eagle groupset to shift well & helps keep the rear mech compact & out of the way of rock strikes. Description by Mark, Rutland Cycling Web Team.