7-745129-4 is a stepped ferrule component used with HDP-20 D-subminiature shielding hardware kits from the AMPLIMITE cable connector series. This ferrule features a stepped style design with an L dimension of .440 inches and is compatible with shell sizes 1-3. The steel construction with tin plating provides durable shielding and reliable cable termination. These ferrules are commonly used in industrial machinery, medical instrumentation, computers and peripherals, and data storage systems where secure cable connections and EMI shielding are required.