Unused, unopened and stored in a heated environment above 32 degrees. I opened one and tested recently and it is very good (see photo). Expiration is one year after opening a barrel.
I have 5 sets left (10 - 55 gallon drums). I'm selling each set for $1800.
This foam has many applications. I bought from AeroMarine Products. Two-part, 2# per cubic foot density foam designed for use in filling cavities and voids for positive flotation. It's also an excellent insulator for use around fridges and freezers and can be sanded into any shape once it's cured. Foam can be covered with poly resin material and woven roving or epoxy resin with cloth to give a strong, durable finish.
Please see the photos for the manufacturer's specs. If interested in buying, please reply with phone number so that we can arrange pick up more easily. I have a drum lifter so that I can load.