The Blue Yo Yo's LEDs are activated once you start playing. Simply flick your wrist, let the yo yo go and watch the bright blue flashing LEDs! 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. Specifications: Diameter: 2.25 in. LED Color: Blue Batteries: Yo Yo comes ready to use with non-replaceable batteries Weight: 0.34 lbs