Sling: A rigid lifting device for lifting operations. Lifting tools can directly lift items, mainly including hooks, grab buckets, clamps, suction cups, and specialized lifting tools.
Rated lifting capacity of the lifting appliance: Under normal usage conditions, the lifting appliance is allowed to bear the maximum mass of the item when vertically suspended.
Rigging: When lifting items, a combination of flexible lifting devices with a hook attached to the item is called a rigging or sling, which is generally composed of high-strength flexible parts combined with end rings, hooks, shackles, etc.
The ultimate working load of a sling: refers to the maximum weight that a single sling is allowed to bear when vertically suspended under normal usage conditions.