This is a 4-tier metal storage rack on wheels. The foldable storage shelf is made of powder coated steel for durability and can accommodate heavy duty trash cans and boxes. This storage rack can hold up to 150 lbs. per shelf (without wheels), or only 60 lbs. per shelf if wheels are installed (top tier is not recommended for heavy items). Non-slip, durable wheels swivel 360 degrees and 2 of the wheels have a locking feature so you don't have to worry about sliding. Folds down to fit in tight crevices, behind doors, etc. to save space when not in use, and the side rails are designed to prevent items from falling. No assembly required, easy to use.