Economical yet very durable racks that are submersible, autoclavable, and easily stack when empty.  Made from a special blend of polypropylene (PP) that makes them sink in a water bath and maintain their stability, even in agitated water.  The top tier features an alphanumeric grid reference.  Available in white, but can be special ordered in various colors. Shipping weight (for pack of 6) 2.0 Lbs., Package dimensions: 15" x 10" x 2".