Since it is safest for your child to travel facing backwards, the Sirona S iSize guarantees a comfortable rear-facing travel position for children up to 105 cm tall and around 4 years old. The direction of travel control prevents the forward-facing transport of children under 16 months and 76 cm tall. Even in the forward-facing position, the Sirona S iSize provides your child with additional safety thanks to its energy reduction technology. This is activated during a frontal collision when the impact energy is at its highest: the headrest glides down to gradually minimize the impact energy on the neck area and then securely locks into a defined position.