Constructed of high-strength fiberglass and reinforced with polyester resin, these LEWISBins+ Plexton Stack-N-Nest Containers are built to last. Stack and nest securely. Resist wear, oil, and most chemicals and are non-conducting. Single containers carry up to 500 lbs., while the bottom container in a stack supports up to 3,000 lbs. Other features include: smooth outer surface and seamless body, permanent, molded-in colors, and built-in hand grips. Made in USA.