Spreader bars are normally made out of pipe and have top and bottom lifting points on opposing ends. They are suspended by a crane from two slings and normally have two to four bottom slings attached for rigging to the load. Custom lifting devices like spreader bars are always in compression and are designed with varying pipe diameters and thicknesses to obtain the proper design factor to meet the maximum rated capacity. Spreader bars are the best choice for loads where the lift points are far apart and load control is important.