Mounted on four spring loaded swivel casters that retract under user’s weight. Working heights up to 12'. 7" deep steps with a 10” deep top step on 1 - 4 step models shown with (*) or (*). 14" deep top step on 4 - 7 step FSH models. Comes standard with expanded metal tread, optional treads available. 1 - 4 step ladders () & (**) ship unassembled in a box, eligibile for UPS;. 4 - 7 step FSH models ship unassembled.