BeSafe iZi Up X3 grows with your child during the whole period of use up to 135 cm (even 150cm in some Countries). The head and back supports can be easily adjusted on both sides of the car seat using a synchronized handle. Not only the headrest but all side impact protection side-parts move when adjusted ensuring the child receives maximum safety regardless of height. BeSafe iZi Up X3 does not need to be installed. Just place it in the car and use the 3-point vehicle belt to secure your child. Locked beltguides that move wider automatically as you adjust the seat height will position the belt correctly over your child’s shoulders away from the neck.