Topeak babysitter rack fdisctopeaks babysitter rack is for use with their babysitter child seat and designed for bikes with disc brakes it has a strong tubular frame and incorporates the quicktrack system making them fully compatible with mtx trunk bags featuresuse with babysitter child seatdesigned for bikes with disc brakesstrong tubular frameincorporates quicktrack systemcompatible with mtx trunk bagsbuy topeak accessories from chain reaction cycles the worlds largest online bike store