Everyone will know there's a birthday in the house when you wear Sparkly Happy Birthday Headbands with Fiber Optics! Brilliant color change LEDs shine through the fiber optic antennas making this funky fun headband attract attention right & left. Surprise the birthday girl or boy when they walk in the room & every guest is sporting a Light Up Headband! Sparkly Happy Birthday Headbands with Fiber Optics are indeed a good time & most excellent party favor. To activate your Happy Birthday Party Hats, flip the switch located at the top of the headband. Words do not light up - they are covered in silver glitter. LED colors will automatically change; there are no other light options. Come in assorted packs of pink and blue. 3 AG13 bastteries are included and replaceble. NOTE: Due to packaging that will save you money on shipping, headbands require light assembly. Fiber Optics arrive separate, so just plug them into the 2 spots provided on the headband.