POLY-GREEN® LEDGE SNAPS ONTO PERIMETER OF PROVIDING 4″H RETAINING LEDGE. IF HIGHER LEDGE IS REQUIRED, STACK FOR 8″, 12″, ETC. POLY-GREEN® FEATURES A GREEN POWDER-EPOXY OVER ZINC-CHROMATE ELECTRO-PLATING THAT HANDLES TEMPERATURE AND MOISTURE EXTREMES WELL. NEX GARD ®, AN ANTI-MICROBIAL AGENT, PROTECTS THE EPOXY COATING FROM BACTERIA, MOLD, AND MILDEW THAT CAUSES ODORS AND PRODUCT DEGRADATION. LIMITED FIFTEEN YEAR WARRANTY. NSF APPROVED FOR WET OR DRY USE.