Size Information: The baby sun hats are available in 4 sizes. 6-12 months head circumference about 18.9 inches (48cm); 12-24 months head circumference about 19.7 inches (50cm); 2-4T head circumference about 20.5 inches (52cm); 4-8 Years head circumference about 21.3 inches (54cm). The age recommendation is only for reference you can choose size selection according to your baby's head circumference. Premium Material: These baby hats are made of high-quality UPF 50+ sun protective polyester fabric which not only keep the baby soft and cozy but also stop over 98% of harmful UVA and UVB Rays! Unique Design: Fits Well & Safe Adjustable chin strap and head strap make this sun hat grows with your baby together. This chin strap is specifically designed to come undone under pressure a safety feature to help prevent choking. Foldable & Packable Lightweight & foldable mater