To activate your LED Mouse Ears, remove the pull tab & slide the switch on side battery house. LEDs glow a steady light, no flash. Toys play a crucial part in development of a child. Toys as simple as wooden blocks or numbered puzzle, develops cognitive and physical skills. Complex puzzles, remote control cars, bubble guns helps learn and analyse cause effects and spatial relationships. Babies tend to play more and more with such toys and make themselves happy. Children's attitude towards their toys nurtures them big way. Note:One size fits most. Black plastic headband is pliable, so give it a stretch or 2 if you're a grown up. Ears come ready to use with 2 replaceable AG13 Batteries.Specifications: Size: 7.5 x 5.75 in. LED Colors: 2 Blue