These conduits are used to protect sensitive electronic circuits such as communications, radar, and data transmission from outside interference or "noise".  The reverse situation is also an issue.  Today's Original Equipment Manufacturers (OEMs) are finding that, if they wish to ship electrical equipment into the European community, they may need to be in compliance wit recently developed CE standard which reduce the allowable amount of EMI/RFI emissions from electrical apparatus.

All three are designed to accept industry standard liquidtight connectors and address the problems of assembly and grounding.  Connectors of this type include a grounding ferrule, which contacts the internal metallic material of the conduit and the connector body.  This produces a direct shield-to-drain or ground, simply by tightening the connector.

The graph to the right depicts the shielding effectiveness (attenuation in dBs) of all three types.  The dotted line shows a comparison to standard unshielded liquidtight flexible conduit type LA.  The spectrum of test frequency is from 1 MHz to 10MHz Electri Field, to 100 MHz to 1 GHz (1000 MHz) Planewave Field.  Tests were performed per MIL-STD-285 on 1/2" trade size conduit.