The Sunrace Rear Derailleur Extended Link is designed to increase the clearance between the rear derailleur mech and the rear sprockets on the cassette.
This useful gear gadget is especially useful where a rear mech is found to be too close to the largest sprockets to function correctly, and especially applicable on several modern cassettes with lowered (larger sprocket) bottom gears.
Fits to conventional threaded rear mech hanger fittings on most frames.
