The big 60mm bulkhead that came with my Eshopps overflow came with 2 gaskets for the bulkhead. Every other bulkhead I have only came with 1 gasket, which I understand goes on the flange side. Do I use both gaskets on the 60mm bulkhead, one on the flange side and one on the nut side? Or is it just an extra gasket just in case?

