The britax kidfix sl in black thunder44 is suitable from 15kgs to 36kgs or 4 years to 11 years offing an older child a safe and comfortable seat44 providing superior protection with the unique isofit system that anchors the child seat directly to the car the 3 point seat belt then secures the child in the seat kidfix44 is unique in its category because of the combination of energy absorption and the isofix technology this means under certain forces44 the car seat will move smoothl