This pair of National Union Type 27 audio tubes with black plates and foil D getters have been tested and are guaranteed to be strong. Made in the United States, these vintage triode tubes are a great addition to any consumer electronics collection. The brand, National Union, is known for producing high-quality audio equipment and these tubes are no exception.

The model 27 tubes are easy to install and will provide a great sound experience for any vintage audio and video setup. Whether you're a collector or just looking to add some vintage charm to your home, these tubes are a great choice. Don't miss out on the opportunity to own a piece of audio history.