We bought this horse trailer, along with the Schleich 4x4 vehicle with driver, for our 3 year old son for Christmas. We also bought a couple more Schleich horses for him to go with the trailer.
Be advised that this trailer is very small and only certain Schleich horses will fit. If their tails or back legs are at all extended, you won't be able to shut the trailer door. This has been frustrating for our son, as only one of his horses will fit.
In addition, if you are considering the 4x4 vehicle, be aware that the doors pop off very easily. When my son tries to open them, the whole door comes off. Luckily, we have been able to pop them back in - however, he prefers now to just take both the doors and the top off.