Ergobaby Infant Insert Material: 100% cotton This is an infant insert, an optional product for Ergobaby baby carriers. I purchased this as a recycled item, but I haven't used it myself and have stored it at home. As you can see in photos 9 and 10, there is one stain. - The Ergobaby Infant Insert consists of an outer insert that gently wraps the baby and a removable bottom cushion. By using these two together, the baby's head, neck, buttocks, sacrum, and spine can be supported in the correct position. - Target age: Newborn (3.2 kg) to when the neck is fully stable (4 months, 5.5 kg) You can use the Ergobaby baby carrier and infant insert in any combination of series and patterns.