i’m afraid could be any number of probably well over a dozen different systems.
The only way to confirm is to take the top cap of the post and take a picture of the extrusion looking down on it. Post that picture and i’ll see if I can help you identify which system it is.
Please note:
This action will also remove this member from your connections and send a report to the site admin.
Please allow a few minutes for this process to complete.