Problem Solvers Cassette spacers allow you to run a cassette on a freehub body not intended for it, to assemble a cassette from loose cogs, or to replace a lost spacer from an otherwise-complete cassette. If youre not sure exactly what you need, we strongly recommend seeking the guidance of a professional bicycle mechanic.

FW8401 Problem Solvers 11spd Freehub Body Conversion Spacer for 10 speed Cassettes on 11speed Freehub, 2mm