Etched codes: f33 X9I. Great durability, double DD getter! One of the most used tubes in audio right now! Great upgrade for any amplifier. Made in Sittard factory, year 1959!
Etched codes: f33 X9I. Great durability, double DD getter! One of the most used tubes in audio right now! Great upgrade for any amplifier. Made in Sittard factory, year 1959!