Baby Hat Size- The hat circumference is 18.9"-19.7",it suitable for 6-24months old baby toddler.The 17.3"-18.5" circumference is fit for 3-12months. Of course, you must first measure your baby's head circumference fit which size.The age recommendation is just a reference, because every child is different. Cap Material- these caps are made of polyester&cotton.Lightweight.Environmentally friendly materials, no harm to the skin, no allergies. Breathable fabrics keep your baby warm in spring and cool in summer. Cap Brim Design- Pre-curved visor offering protection from the glare of the sun. The Velcro in the back of the cap can make the cap become bigger or smaller, The cute pattern and animals ears make your little boy or gril more lovely. Cap Function- It protects your little one's eyes from the sun. Quick dry fabric, breathable mesh panels & comfort sweatband inner for cool in the hot summer. Cap Washing Tips- 1. Hand wash, do not use chemical detergent to wash. 2.Can't force rubbing,twisting twist,so as not to cause hat deformation;only gently rubbing.