SHELF CLIPS SNAP ON POST, ALLOWING SHELF COLLAR TO SLIDE OVER FOR A SECURE FIT. OPEN DESIGN MAXIMIZES AIR AND LIGHT CIRCULATION AND MINIMIZES DUST ACCUMULATION.BRIGHT, CHROME OVER NICKEL ELECTRO PLATING CREATES A BRILLIANT HIGH GLOSS FINISH. ESD CASTER TRUCKS INCLUDE 4 SHELVES, 4 POSTS, 4 SETS ALUMINUM SHELF CLIPS, 1 DRAG CHAIN, AND 4 POLYURETHANE ESD SWIVEL CASTERS, 2 WITH BRAKES.