This is a light relaxation item that tells time through the phases of the projected "moon." When placed about 2 meters away from a wall or ceiling, it projects a realistic moon with craters, approximately 60cm in diameter. The moon gradually changes from "full moon" to "new moon" in a cycle of about 1 hour. Body size: Approximately 100mm Batteries: Required, 4 AA batteries Product dimensions: 13.79 x 13.59 x 13.41 cm 358.34 g Box-shaped, no instruction manual. Outer surface has scratches. Operation confirmed. Stored at home.