Apollo-era dinitrogen tetroxide fill and drain valve, measuring approximately 5.25″ long and 2″ in diameter, marked on the cover, "Coupling-Class 2, Type IV, N2O4 Fill & Drain Disconnect, NAA/S & ID Cont No. ME273-0019-0002." Also marked on the side with several inspection stamps, additional numbers, and a date: "6760-4, S/N 6263, 9/25/72." The valve has a unique locking mechanism for opening and closing.
