The 5881 Final output power beam Tetrode valve (also 6L6WGB) is nothing more than a super special version of the best known 6L6 and all its other variants but with an increase in power dissipated in the Plate and Grid of 20% in more. Produced by TUNG-SOL and also by SYLVANIA, it was exactly conceived as a power amplifier and therefore ideal for use in Low Frequency AUDIO. Powerful and Dynamic Sound but above all excellent structure, robustness and compact dimensions are the main aspects of this valve which make it highly resistant to shock and vibrations and therefore ideal for amplifiers for musical instruments, often moved from one stage to another. Made in the early 1950s, it was a GREAT success and, at the time, advertised together with other legendary tubes of this brand such as the 5687, 6U8, TS2, TS-21. This is a GENUINE and ORIGINAL (NOT Russian production today!) PAIR of 5881 TUNG-SOL made in USA in perfect aesthetic and electrical condition, Same code and TEST over 100%, paired. EQUIVALENT: CK5881 = 6L6WGB = CV2796 = CV1269 = 5932 = 6L6 = 6L6G = 6L6GC = 6L6GB & REPLACEABLE: KT66 = EL35