Metal canister C2A! filter with 40mm thread. This has been the basic NBC / CBRN filter canister for U.S. Troops for many years now. These are military surplus filters, vacuum sealed, New Old Stock. The dates and lots will vary but they are all the older style C2A1 in the metal tub, not the new C2A1 filters in the plastic cans (see separate listing).
These are government surplus that were stored properly to our knowledge. These are out of date but are still sealed. They are guaranteed from the manufacturer for 10 years from the manufacture date; however it is very possible that these are still perfectly fine. That is assuming that they continue to be stored properly.
Please note that most of these will have minor dings and scrapes on the outside of the can, but will still be fully intact.