Neon Nightlife Light up Fedora Small/Medium size fits heads sized 22 inches in circumference or smaller. Large size fits heads sized at 23 inches in circumference or smaller. Light controller takes one AAA battery and has 3 settings: Full On, Blink, Off. Battery pack is velcroed to the inside of the hat & out of the way (no dangling wires while in use) Fedora lights will remain bright for up to 10 hours with a new battery Perfect for Concerts, Rave Festivals, Bars, Clubs, Electric glow run, LED parties, Halloween, Costume Parties, Mardi Gras, Carnivals, Gifts, and more We offer a 90 day warranty on the product. If for any reason the fedora breaks under normal usage, we will replace it within 90 days.