Fun interactive materials keep baby engaged. Velvety soft cover, crinkle pages and peek a boo flap Button for night sounds, music, and lights. Includes replaceable batteries Appropriate for ages 0+. Follow The Very Hungry Caterpillar as he works his way through this Twinkle Twinkle Little Star soft book on his way to see the firefly light up! This soft book includes both sounds and lights. Press the sleeping caterpillar on the last page to hear nighttime critter sounds and to hear the song Twinkle Twinkle Little Star. Press again to see the firefly light up.