? Good for all seasons to block the sun for toddlers! ? For 3-5 years old children in general. ? Inside crown measurement is about 19"-20" (48.20 cm to 51 cm) ? I would say measure child's head (crown) and make sure it doesn't exceed 20.5 inches. ? Wash by hand in warm water. Shape the hat out and let it air dry. ? Material: Cotton ? So far we have only one size and sorry we don't take customization at this point.