Ultimately, it is a booster seat incl. Back. The back can and should be removed for larger children. The approval for the back is only for children up to 25kg. The manual is a joke. Thus, the correct height adjustment is not apparent from the drawings simply. I hope I'm doing it right .... Then there is a sort of "catch clamp", which is nowhere described. Also, since it is left to its own fanatasie how the part is to be used. But for "Grandma's car" that part is certainly capable. As I said, the instructions should be überarbetet and are also provided on the website for download.