What are shackles and how are they used in rigging?

A shackle is a U-shaped metal connector with a removable pin, used to join rigging components together. Screw-Pin-Anchor (SPA) shackles are the most common type in entertainment rigging. They connect chain motor hooks to wire rope, wire rope to spansets, and virtually any other junction in the rigging chain.

Every shackle has a stamped working load limit (WLL) that must not be exceeded. Shackle pins should be inserted fully and tightened to finger-tight only, never wrench-tightened, because over-torquing can deform the pin and compromise the shackle's rated capacity. Only use rated, certified shackles from reputable manufacturers. Shackles are available in sizes from 1/2" to 1" and larger, with WLLs ranging from roughly 1,000 lbs (1/4") to 13+ tons (3/4"). Your rigger selects the shackle size based on the load at each connection point.