XX Small – Suitable for babies who have chest circumference between 16 and 25 cm and weight under 2.72 kg.
X Small – Suitable for babies who have chest circumference between 25 and 34 cm and weight between 2.72 and 3.17 kg.
Small – Suitable for babies who have chest circumference between 34 and 43 cm and weight between 3.17 to 4.53 kg.
Medium – Suitable for babies who have chest circumference between 43 and 52 cm and weight above 4.53 kg.
Large – Suitable for babies who have chest circumference between 52 and 61 cm and age over 2 to 3 months.