Corrosion-proof performance, proven Metro stability, and unrivaled value. All polymer shelves with removable, easy-to-clean 6" wide shelf mats. Shelves adjust in 1" increments. Lifetime warranty against rust and corrosion. Built-in Microban antimicrobial product protection to keep the product "cleaner between cleanings." Add-on units consist of two posts and indicated number of MetroMax 4 shelves along with two "S" Hooks per shelf, for attaching shelf to adjacent unit in an end-to-end configuration. L-shaped configurations require a Corner Add-On "S" Hook kit (MAX4-CNR4/MAX4-CNR5, sold separately).