life-size two piece harvey skull has a movable jaw that is spring loaded. Great feature on this skull is the spring is hidden and is not visible from normal view. Very realistic skull with moderate detail for this price point. The skull is hallow and made of pvc plastic, which is basically what all anatomical models and skeletons are made of. Size is 7" from back of skull to front, 5" wide and 6" tall; and weighs just under one pound at 14 ounces. Who doesn't need a few skulls?