Piece of pool which I dont know the name of

Hello,

My wife and I are purchasing a home which has a in ground fiberglass pool. While walking around it, I noticed that there is a plastic ring which appears to fix to the top of the pool probably 2 inches in height and attempt to close the gap between it and the above concrete coping I think.

Anyway, this ring is loose (kind of like a washer that goes around the entire top of the pool) and is coming off in areas (appears to have screws holding it in). Is this something to be overly concerned about in regards to being expensive to repair? I wish I could attach a picture, but it does not appear that I can.

Thank you,

-Jeremy