Good looks apart, BMW’s child seat comes with a height-adjustable backrest including a belt carrier and side support as well as a headrest for extra safety. What’s cool though is the fact that the backrest and side support interact with one another, automatically adjusting the seat width as a function of seat height. As a result, the seat literally “grows” with the child sitting in the seat, the correct position being shown by a centimeter scale on the backrest indicating the body height currently set on the seat.