Upgrade or replacement rear derailleur dropouts stiffer and more rigid to improve shifting performancecnc machined from solid 6061 aluminium to exact tolerancesstiffer than any original equipment hanger whichimproves shifting performancestill breaks before your frame does to perform its main functionall hangers come with instructions and hardwaredirect replacement for original equipment with guaranteed fitblack anodised for extra scratch and damage resistancelaser etched for easy part identific