The 4-layer metal storage rack includes a small spanner and four caster wheels which two are lockable. The wheels are composed of high-quality PP material for durability. PRE-ASSEMBLED: Unfold the shelf and install the wheels using the spanner that comes with the package. Yes, you heard it right. It’s that simple! This shelf organizer is one of the easiest storage racks to clean. Simply wipe the surface with a damp cloth to clean the shelf, keep it dry, and do not submerge in water. The metal shelf rack is suitable for a wide range of applications. This heavy-duty metal can prevent the shelf from corrosion. The mesh racks on both sides can also prevent objects from falling. The free-standing unit can hold up to 200 kg, each tier holds up to 50 kg approximately.