The 97-60-14(621) is a Protection Cap with black zinc alloy plated finish. The dust cap/cover comes with a beaded chain, cadmium olive drab finish. The cap for receptacles have internal threads and is used on MS3102, MS3101 and MS3100 receptacles. A soft rubber disc seats on the connector shell, forming a water-tight joint. It is suitable for use with the 97 series MIL-C-5015 circular connectors.