Extra Heavy Duty: Complete with rail shield, large extruded aluminum top with tool tray, heavy 3 3/8" aluminum steps, each step and rear bar is braced.
Heavy Duty Metal Top: Extra heavy duty slip resistant vinyl feet, 3" aluminum steps, inside aluminum spreaders, aluminum top with tool tray, and solid aluminum rivets.
Heavy Duty Plastic Top: Same heavy duty construction as model #3715 with a molded plastic top.