This is a SYLVANIA 12AX7WA vacuum tube for the US military. The WA mark indicates a vacuum tube that is highly resistant to vibration, has low noise, high performance, and a long lifespan. It was primarily used in military communication equipment, high-end audio equipment, guitar amplifiers, etc. I am selling this to clear out my inventory. I have tested it in a real device to confirm that it produces sound before listing it. It is a beautiful product, almost unused. Please take a look at the photos and consider it for your amplifier's EQ, etc.