Volume B30.20 includes provisions that apply to the marking, construction, installation, inspection, testing, maintenance, and operation of below-the-hook lifting devices, other than slings, used for attaching loads to hoist. The devices are arranged in five chapters as follows: Chapter 20-1: Structural and Mechanical Lifting Devices; Chapter 20-2: Vacuum Lifting Devices; Chapter 20-3: Close Proximity Operated Lifting Magnets; Chapter 20-4: Remotely Operated Lifting Magnets; and Chapter 20-5: Scrap and Material Handling Grapples.