Abstract: Disclosed is apparatus for maintaining free movement of an object such as a steel or glass ball in a pressurized container which includes a flexible chamber for isolating a product and a propellant for the product. The object is freely movably disposed in the product and is adapted to mix the product upon shaking the container. The apparatus according to the invention comprises an elongated base having a plurality of spaced-apart protrusions projecting outwardly from the base. The protrusions extend from the base spaced from an end thereof. The apparatus is adapted to be secured in the container with the end of the base disposed at the bottom of the container. The apparatus maintains a path of free motion for the mixing object and in the case of an expandable chamber which contains the propellant, allows maximum expansion of the chamber without preventing or impeding motion of the mixing object.