The Topeak BabySeat II with Disc Compatible Rack features a wrap-around seat structure for added protection. An updated shoulder harness with a multiple height adjustment system increase fit and a innovative suspension system cushions bumps and jolts. For 26, 27.5 (650B) & 700c wheels with disc brakes Integrated roll bar provides extra head protection and doubles as a carrying handle Adjustable footrests and straps keep small feet away from spinning wheels. Child seat complies with stringent European, CPSIA and Proposition 65 safety standards The included heavy-duty disc mount rack features an innovative BabySeat attachment that requires no tools to attach and remove seat from rack QuickTrack rack system is compatible with all Topeak MTX TrunkBags and MTX Rear Baskets Rack dimensions: 13.4 x 9 x 15.7