Four models that all feature one piece extra-strong seamless polyethylene construction. Bins will not leak, dent, pit, corrode or absorb moisture. 12-gauge, 7/8" reinforced/welded tubular steel frame is designed for maximum strength and maximum weight. Easily handled by one person. Smooth interior walls prevent adherence and build-up of debris and contaminants.Can easily be cleaned with steam or high-pressure hot water. All exposed parts are protected by rust-preventive grey enamel.Most models are equipped with deluxe roller bearing wheels with grease fittings and solid rubber heavy-duty swivel casters, providing full maneuverability, stability and longer life span. Optional vinyl cover fits snuggly with elastic band, keeps debris in andweather out.