Allied Electronics Corporation offers Metric Shell. Allied Electronics Corporation is an ISO 9001: 2000 certified company. The Metric Shell Style comes in various types. There are fixed connectors without back shell [sleeve]; free connectors with straight sleeve; free connectors with angular sleeve; free connectors without sleeve; free connectors [cable mounted] with straight sleeve and free connectors [cable mounted] with angular sleeve. It is used in the Circular Connector Industry.