ADDITIONAL HEAVY DUTY SHELVES CUSTOMIZE YOUR HEAVY-DUTY SHELVING UNITS WITH ADDITIONAL SHELVES. SHELVES ADJUST WITHOUT UNIT DISASSEMBLY ON 4 PLASTIC SLEEVES (INCLUDED). THE POLY-Z-BRITE FINISH INCLUDES NEXGARD , AN ANTI MICROBIAL COMPONENT THAT FIGHTS THE GROWTH OF BACTERIA AND MOLDS AND A 15 – YEAR LIMITED AGAINST CORROSION. NSF APPROVED.