Channel Vision panel knockout

My 50" Channel Vision structured wiring panel has a knockout on the top that is about 7" wide by 1-3/4" deep. The "ends" of the knockout are rounded, i.e., it the knockout has the look of the cross-section of an oblong pill.
 
Is there some type of wiring raceway, channel, etc., that fits this, or is it just a big knockout that doesn't fit anything in particular?
 
Thanks,
Ira

Passthrough for LV cables.

You can buy flexible grommet edging to line it, if you want. Thought Elk or Channelvision sold it, but can only find Panduit currently.

I think my CV enclosure came with some of it.

http://www.performance-pcs.com/solid-wall-polyethylene-grommet-edging-with-adhesive-clear.html