Why height, not age
i-Size seats (UN R129) are sized by your child’s height, which is a more reliable guide than age. Measure your child standing, without shoes.
Our three seats
Cybex Sirona Ti i-Size: 40–105 cm, from birth. Cybex Sirona Gi i-Size: 61–105 cm, from about 3 months. Cybex Solution T i-Fix Plus: 100–150 cm, about 3 to 12 years.
Where they overlap
Between 61 and 105 cm both Sirona seats fit: we suggest the Sirona Ti for babies under about 76 cm and the Sirona Gi above. From 100 to 105 cm a child can stay in a Sirona or move up to the Solution T booster.
Not sure?
Use our car seat finder, or tell us your child’s height when you book and we’ll set the seat up for it.