The BOLANY derailleur hanger extension is a unique device that offsets the position of your road derailleur to make it possible to run a wide-range mountain bike style cassette.
Tech Specs:Easy to install in less than 5 minutes
Material : 6061 aluminum alloy
Bike Type: Road Biycles / Mountain Bikes
Packcing included: 1pc screw
FOR Wide Ratio Cassettes
Weight :about 10g.
Application: use for rear derailleur extension, apply for 40T/42T/46T/50T mountains freewheel or 32T/36T flywheel,
to extend the flywheel speed and change it more smooth.
NOTE: Due to measured by manual, there will have1-2mm different. Hope you can understand, thanks.