To activate, turn the switch located on the back of the headband. One size fits most. NOTE: The Bunny Ears are bendable, but do not bend on their own. Height: Approx. 12.12 in. , 30.78 cm. – Width: Approx. 9.75 in. , 24.76 cm. LED Colors: Blue, Jade and Red Batteries: Includes 3 replaceable AG13 batteries. Weight: 0.51 LB