Conduit Body Gasket 2-1/2″ to 3″, Neoprene, Rain-Tight Seal
https://dev.nsiindustries.com/product/conduit-body-gasket-2-1-2-to-3-neoprene-rain-tight-seal/
Bridgeport conduit body gaskets are used to create a seal between a conduit body and its cover. Neoprene gaskets are dust-tight, rain-tight and impervious to most other liquids and oils.