The shackle is a widely used connection tool. It can be used to connect various cables and chains, as well as to connect buoys and buoy chains. It can also be used to fix cables and chains to devices such as deck eyelets (plates). The buoy shackle is an intermediate component that uses chains to fix buoys to provide berths or build anchorages. Shackles are widely used because of their small size and large load-bearing capacity. According to the type, they can be divided into G209 (BW), G210 (DW), G2130 (BX), and G2150 (DX); according to the type, they can be divided into bow-shaped (omega-shaped) bow-shaped female shackles and D-shaped (U-shaped or straight) D-shaped female shackles; according to the place of use, they can be divided into two types: ship use and land use.