For 26\", 27.5\"(650B) & 700c wheelsA wrap-around seat structure creates a virtual cocoon of protection and features an updated shoulder harness with a multiple height adjustment system. An innovative suspension system cushions bumps and jolts and the integrated roll bar gives 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 rack features an innovative BabySeat™ II attachment that requires no tools to attach and remove seat from rack. Once the seat is removed, the exposed QuickTrack™ system is compatible with all Topeak MTX TrunkBags and MTX Rear Baskets.Seat Body  : Molded engineering grade plastic.Safety Features  : Adjustable foot rests with straps,Roll bar handle,Shoulder harness with multiple height adjustment system,Full body cocoon,Rear reflector.Suspension  : Dual steel spring.Rack : 6061 T-6 hollow aluminum.Max. Weight Capacity (BabySeat)  : 22 kg / 48.5 lb.Max. Weight Capacity (Rack)  : 25 kg / 55 lb.Bag Compatibility : MTX QuickTrack™ system.Size (L x W x H) : 58.5 x 39.5 x 77.4 cm,23” x 15.5” x 30.5” (Seat),34 x 17 x 40 cm,13.4” x 6.7” x 15.7 (Rack).Weight : 3.13 kg / 6.9 lb (Seat),580 g / 1.27 lb (Rack).