There are 3 kinds of often-used swivel shackles including swivel link, Type A swivel, and Type B swivel. The Type K and other less often used ones will not be listed here, but we can trade them as well. Swivel and forerunner are used to connect anchor and chain, meanwhile to avoid chain twisting in order to lift anchor fluently. Forerunner is length of chains with fixed structure, composed by a swivel, common links, enlarged links and joining shackles, etc. Mostly a swivel forerunner is going together with anchor chain on ships. Pls see more details from below link: http://www.ekaship.com/anchorchain/what-is-a-anchor-chain-forerunner-15.html
