Junior-Series - Scale 1:24 - it has got the same parts and sizes of the Profi-Series in 1:16, but the models doesn't have a steering and the bottom side of the Chassis is open. Thus, the tractors are more easy to assemble and it takes less time. Still we recommend, if kids want to assemble the tractors, that parents will accompany their children for the first 50 % of the assembling time.