What does “NOS” mean?
A. NOS stands for “New Old Stock”. This means that the product (tubes in this case) have not been used previously and are of a previous model or brand (usually that is no longer produced). Keep in mind that NOS does not always mean that the tubes are as good as when they were new. Most of the time, they’ll be fine, but there’s always the possibility that they have degraded over time. Caveat emptor.
