These cases have all the familiar features of the standard Heavy-Duty Shipping Containers plus the added feature of having factory installed 2" low profile ball bearing wheels. Each wheel can support 75 lbs. You can now roll these cases around your plant or shipping docks without a problem. Super rugged for air, sea or ground transportation or for simply storing sensitive electronic equipment. Should a case be dropped, its High Density Polyethylene construction protects your equipment by absorbing some of the energy before it is transferred to the contents. All containers are waterproof but not submersible and feature an attractive, easy to clean, off-white color. Depending on the case size, either two or four wheels are mounted to ensure maximum stability. One year warranty against manufacturing defects.