Babies between 3.2 kg and 5.5 kg must use the baby Infant Insert with the baby Carier, and the baby should only be carried in the front-carry position. Babies more than 5.5 kg but younger than 4 months or without strong and consistent head and neck control must continue using the baby Infant Insert with the carrier. Neither the baby carrier nor the Infant Insert should be used for children under 3.2 kg