4 in center swivel back caster and 10 in inset wheels for smooth handling and maneuverability. Constant force design allows for controlled dumping by one person. Created with seamless one-piece rotomolded plastic bodies and reinforced lips. Won't rust, dent, chip, or peel and is easy to clean. Features a powder-coated steel frame for corrosion resistance. Easy to maneuver through commercial doorways and onto elevators.