Need help selecting the correct top rails and caps that will work for our pool. I do not know the brand or model of it. I have included pictures of what you ask. Please let me know - thanks!
Jenny
Size of the pool & approximate age of the pool? - 21ft round
* Image of the pool wall. 48" picture included
* Image of the upright picture 
included
* Image of the top rail connection to the upright. included
* Name & age of the pool (if known) do not know.
