Slat steel on 3 sides extends 48" high above deck to help contain loads and improve visibility and airflow. Shelves are adjustable on 3-1/2" centers for versatility, and can be positioned with 1-1/2" lips either up or down. Shelves are 12 gauge steel. 3600 lbs. overall capacity with non-marking, long-lasting 6" x 2" polyurethane casters, 2 swivel, 2 rigid. Overall height is 57". Additional factory installed adjustable shelves are also available.