The height group is a classification that makes it easier to choose the right car seat based on the height of the child. This system, also known as i-Size certification, is part of the latest European standard R129. Car seats are divided into several groups to provide optimum protection and comfort for children of different heights. For example, car seats for the smallest children are designed for rear-facing use, while for larger children there are seats that can be used in both directions. Although the height classification offers a useful tool for choosing a car seat, it is important to remember that these are only guidelines. Each child develops individually, so in some cases it may be more appropriate to choose a car seat that better suits the child's particular needs and characteristics.