Gro-With-Me: Drawstring head adjustment & adjustable chinstrap ensure perfect fit and longer use Water Repellent: Bionic-Finish ECO fluorine free DWR coating on the fabric surface repels water Superior Sun Protection: 50+ UPF aqua dry water-repellent fabric for best sun protection and comfort with wide brim strengthened to stay up in front Stay-on: Chin-strap ensures hat stays put when windy or child pulls Safe: Break-away safety clip on the chin-strap Pack-able: Light weight and easily foldable to fit in a pocket for easy storage and travelAqua-Dry Adventure Hat Sizing: S: 0 6 months, head up to 45cm (17.7) with 6.5 cm wide brim M: 6 24 months, head up to 50cm (19.7) with 7.5 cm wide brim L: 2 5 years, head up to 53cm (20.9) with 8.0 cm wide brim XL: 5 12 years, head up to 56cm (22) with 9.0 cm wide brim