This 1961 Foreign Tube Interchangeability Guide Radio Substitute Book Booklet US is a must-have for any radio collector or enthusiast. It provides valuable information on tube interchangeability, making it easier to find substitutes for hard-to-find tubes.

With its comprehensive guide on radio tubes, this booklet is perfect for those who want to expand their knowledge on vintage radios. It is in great condition and comes from a smoke-free home. Don't miss out on this amazing find!