I'm thinking it is a check valve cleanout but I can't reference it.This appeared in a sewer trap pit in a residential home in Staten Island NY. It did not have a conventional 2 cap trap. It seems some modifications were made to this pit area to prevent flooding. I can identify the exact device... Any ideas. Thinking it is a check or back flow device...? Click to Enlarge 98.78 KB Click to Enlarge 94.4 KB