The Metro TTM21K4 Track Shelving Kit is designed for efficient storage solutions. This Super Erecta® Top-Track Mobile Unit Kit features 21-inch wide Metroseal Gray epoxy-coated posts that are corrosion-resistant and equipped with Microban® antimicrobial protection for enhanced hygiene. The kit includes durable casters and caster channels for smooth mobility, along with donut bumpers and roller bearing assemblies for stability and ease of use. One kit is required for each mobile unit, with shelves sold separately, allowing for customizable storage configurations.