CHAIN CONNECTOR LINK

A hammerlock is a coupling link used to connect chains to other fittings when the inner dimension of the chain link does not provide adequate space. They are made from quenched and tempered alloy steel for high tensile strength and ductility, and consist of two separated body pieces, a tapered shaft, and a sleeve. It can be easily assembled and disassembled using only a hammer and punch.  
Hammerlocks, also called chain connectors, are often used to connect Winch Hooks to steel cable or synthetic winch rope. They consist of a recessed pin that runs through the ends of the sleeve, allowing it to rotate while remaining securely joined.