FSA Headset Reducer 1.5in - 1 1/8inThe FSA Headset Reducer 1.5in - 1 1/8in is a kit designed by FSA that reduces the internal diameter of a 1.5" headtube down to 1-1/8" so that you can fit a traditional 1-1/8" fork as well as a traditional headset can be installed.400310008404