Commonly known as "NOS," the term New Old Stock simply refers to tubes that were made years ago but have never been used. Much like antiques, "NOS" tubes are currently not being manufactured and this means their supply is dwindling while the price continues to rise.
For most NOS tubes we have a variety of brands available. Typically these are the common brands such as RCA, Sylvania, GE, Raytheon, etc. However, there are instances where lesser known brands are in stock. If you have a particular brand you prefer you can simply request it in the Order Comment box when you place your order.