Screw Pin Anchor Shackles come in two types: Galvanized Steel and Stainless Steel. Galvanized steel is less expensive but can only be used around freshwater and it's lifespan is lower than stainless. Stainless steel is necessary around salt water because it's better suited to withstand corrosion. Stainless steel can be used around any body of water and has a longer lifespan than galvanized steel. Anchor shackles come in different designs, but HarborWare carries the bow-shaped variety.
To attach an anchoring system to a shackle you may also need dock cable. Simply thread the cable through the eye of the shackle and unscrew the screw pin to attach the shackle to whatever anchor device you are using. If you want to use anchor shackles for a boat anchor, then you can attach a chain link to the eyelet in place of cable.