This fonts are authors' property, and are either shareware, demo versions or public domain. The licence mentioned above the download button is just an indication. Please look at the readme-files in the archives or check the indicated author's website for details, and contact him if in doubt. If no author/licence is indicated that's because we don't have information, that doesn't mean it's free.
Fontstruct's first vacuum tube font!
This is a design inspired by Nixie tubes. Since these "tubes " are iconographic, they could theoretically represent 12AX7s, 6L6s, KT88s, or whatever tubevalve you wanted. Feel free to clone and build on this concept.