Material. Steel. Special Heavy Duty Coil Racks, 40 Perfect Steerable Transfer Carthes Long and 4" Wide with 3 peaks on each end. Coil Racks are also known as coil chocks or coil bunks, are Custom in conjunction with hardwood timbers to stabilize metal coils in the load securement process. 2 Guage Steel, 7mm thickness. Quote Now.