The recommended age range of the Ergobaby 360 Cool Air is the same as our Four Position 360 baby carriers. It supports babies from 12 up to 45 lbs / 5,5 kg up to 20 kg with the carrier only, and babies from 7 to 12 lbs / 3,2 to 5, 5 kg with the use of the Ergobaby Infant Insert (sold separately). Infants more than 12 lbs / 5,5 kg but younger than 4 months or without strong and consistent head and neck control must use the Infant Insert with the carrier.