What unique characteristic defines a spelter socket?

A spelter socket is specifically characterized by its method of securing the wire rope through the use of molten zinc or resin. When wire rope is inserted into the spelter socket, the molten material is poured into the socket, where it solidifies and creates a strong bond around the wire. This method enhances the durability and strength of the connection, making it suitable for heavy lifting and rigging applications.

This unique feature differentiates a spelter socket from other types of connectors that may use different methods for securing wires or cables, such as crimping or mechanical fastening, which do not involve molten materials. The choice to use molten zinc or resin is primarily due to its superior ability to fill the voids and create a robust, integrated connection that withstands significant loads.

The other options do not apply to the defining characteristics of a spelter socket, as they focus on aspects that are either irrelevant or incorrect in the context of this type of rigging equipment.