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These are usually removeable but i wouldn't recommend yanking it incase you take the vinyl layer off around the edges.

In our office there is a cap, taking the cap off reveals a neat hole for cables like you see, this is essentially one big piece of ribbed plastic to keep it fixed against the chipboard desk. They usually can be worked out by turning and pulling up at the same time.

If it's not moving i wouldn't force it.
 
You can take the Grommet out by using a Flat head screwdriver to pry it out bit by bit. Work you way around it.
You can use the cardboard from a Cereal box or something similar to protect the surface from the screwdriver.

You might be able to tap it out from underneath with your flat head screwdriver and a hammer also (tapping it on the 2mm edge working you way around). Have a look - it might be way faster for you.

Tappa Tappa Tappa.

Just take you time.
 
Really? It is a cable port on an office desk/table. The cover pops out from the bottom to let the large end of the cables through then snaps back in to tidy the bundle of cables together.
 
there is no bottom, it goes half way down the hole. I tried to push and pull, but nothing seems to happen, I may have turned it half an inche or so, but it is extremely hard to take it off.
 
It might be "keyed" to a certain position relative to a clock dial but I doubt it. This looks like a different type but you may find your's if you look.

41YWNCEi16L.jpg
 
Mine is extremely simple. It looks like the guy used a hammer so I could never take it off.
 
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