Yes I mistyped, meant anti-seep collars. We make them out of 1/2" PVC board, comes in 4x8 sheets from Lowes. It's not cheap but you can get several out of a sheet. For pipes 8-12" we make them 2'x2', cut the hole to fit as tight as possible around the pipe, then seal with silicone. Adjust size accordingly for larger or smaller pipes.