Many companies ordered tubes from tube makers with their name printed on them, hard to know who actually made the tube.
https://audiokarma.org/forums/index.php?threads/did-fisher-make-their-own-tubes.617033/
Sometimes a code can get you to the actual tube manufacturer
https://www.vivatubes.com/identifying-vintage-nos-vacuum-tubes-by-brand-country-and-eia-code/
https://audiokarma.org/forums/index.php?threads/did-fisher-make-their-own-tubes.617033/
Sometimes a code can get you to the actual tube manufacturer
https://www.vivatubes.com/identifying-vintage-nos-vacuum-tubes-by-brand-country-and-eia-code/