There are three basic materials which ice cube trays are commonly made from. Most consumers are familiar with plastic ice cube trays, which are flexed to loosen the ice cubes so that they fall out. Over time, however, plastic trays have a tendency to crack, which can be quite irritating. Metal ice cube trays are also available, typically with a handle which shifts a movable section to break up the ice cubes. Finally, many companies make ice cube trays from silicone, a highly flexible material which can be molded into a variety of shapes.