Flap happy original upf 50+ flap hat is designed to provide excellent sun protection from damaging uv rays. The flap hat has a large brim to shade the face, as well as a flap to cover the ears and neck from the harsh rays of the sun. An elastic band built into the hat above the ears provides a more snuggly fit around the head. This hat looks terrific when paired with flap happy swimwear and playwear, and it is perfect for any outdoor or water activity. Your child will love to wear this hat for its comfort it is available in an array of colors and fun prints, making it an easy gift. If you would prefer the flap hat with an even more snug fit, please view the flap happy flap hat with ties flap happy hat size chart, measured head circumference in inches: x-small fits 14-15.5 0-3m, small fits 15-17 about 3-6 months. Medium fits 17-18.5 about 6-12 months. Large fits 18.5-20 about 12-24 months. X-large fits 20-22 about 2 years and up. Xx large fits 21-22.5 about 3 years and up.