HIGH DENSITY POLYETHYLENE, CORROSION RESISTANT CONSTRUCTION IDEAL FOR WAREHOUSE LABORATORY, HOSPITAL, SCHOOL AND GENERAL USE. SHELVES HAVE A RETAINING LIP ON FOUR SIDES TO KEEP CONTENTS FROM FALLING OFF. LARGE, EASY GLIDE 4″ RUBBER WHEEL CASTERS, 2 WITH BRAKES. CONVENIENT PUSH HANDLE EASES MANEUVERABILITY. ASSEMBLES EASILY. !!