Use the XEB-WC when the unit is mounted on top of the fixture. The XEB-WC covers the wiring that goes from the battery pack into the fixture.
Use the XEB-CGM when the battery pack cannot be mounted on the light fixture. The battery pack is mounted on the XEB-CGM, which is then mounted onto the ceiling grid.
The remote Test Assembly (RTA) allows for remote mounting of the test switch and indicator light. The RTA consists of a 3' section of flex, junction box, and cover. (For use with old style units only)