Made with a durable & water resistant nylon material, these caps are lightweight and breathable for our tiny friends to rock comfortably all year long. Sizing: All of our hats have a flexible Velcro latching system to allow for littles to adjust and grow with your caps. Infant: (Coming soon) Designed to fit 0-9 months Size 1: Designed to fit 9-24 months Size 2: Designed to fit 2-5 years old. If you are unsure on sizing, please measure your child's head and/or check out our size guide