Sure !! Techno... well for what i found on my Fryette FB cab was a very thin layer of foam but it went off disintergrate tear off after i took out the p50es with some good amount of degoo it liquid....
I probably go with this instead to cut off some costing as i am from singapore and shipping cost is terrible these days....
Should be the material used for speakers closed cell neoprene... but ya need a gasket cutter to go round ... will ask what material normally used too if Jim is cool to tell i guess he will ...
The front-mount speaker gaskets always came in the box with new Celestions, and relatively few ever end up using them. They were much thinner than the gaskets already attached for standard rear-mounts. Surely Celestion would send you some for a fee,,,,,I'd hope anyways.