Can I use the Raco low voltage partition with a flat mud ring? Looking at their catalog, it says it's only compatible with the raised rings. But it looks like the flat type has a slot in the middle for it?
http://www.hubbellonline.com/wiring/raco_bell/pdf/a30.pdf
http://www.hubbellonline.com/wiring/raco_bell/pdf/a30.pdf