Lightweight, durable fabric is wind- and water-resistant and made of 100% recycled nylon faille with a durable water repellent (DWR) finish made without perfluorinated chemicals to resist light moisture Protective Brim Brim provides shade to keep cool Buttonholes in the hat allow the chin straps to thread onto the reverse side; the chin strap secures with a hook-and-loop fastener Reversible Features Reversible style with fun color combination - light blue on one side and darker blue with fish on the other Pack It In Hat packs small and is easy care There is no size tag but it is size 6-12 month which fits 17.5 - 18.5 inches heads. My son’s head is in the lower percentile, he is a little over 1 year and this still fits.