To activate your Flashing Pink Heart Head Boppers, slide the switch on the side. LED hearts light up a steady bright pink. NOTE: One Size Fits Most! For large heads, the plastic band is pliable & easy to manipulate. Bend the springs too if you’d like. Dimensions: Height 9.5 in. Headband Width 5 in. Heart Height 2.5 in. Heart Width 2.5 in. LED Colors: 2 White inside pink heart shells. Heart Head Boppers include 3 replaceable AG13 Batteries.