Classification of child seat(for reference only) Child seat of grade I : Child seat of grade II : Child seat of grade 0/0+: For a baby or young child less than 4 years old weighing 9 kg to 1 8kg, it is best to select the grade I child seat equipped with seat belt. For children less than 7 years of age, weighing 1 5kg to 2 5kg, it is best to use the grade II child seat together with the three-point seat belt. For infants less than 18 months of age and weighing less than 13 kg, it is best to use grade 0/0+ child seat which can be adjusted to a lying position. 29