The Lullaby Player contains four preprogrammed audio selections, ranging from natural sounds to a melody of lullabies. You can program it to be voice activated or to turn on when baby cries -- then either shut off or have continuous play. Includes soft glowing nightlight and a child-resistant control panel cover. Attaches to crib rail or can be used on tabletop. Requires 4 "AA" alkaline batteries (not included).