EIA manufacturer code 188 identifies General Electric (GE), based in USA. Etched side dots, side-welded plates.
The EIA (Electronic Industries Alliance) manufacturer code system was used on vacuum tubes, transistors, and other components to identify the factory of origin. The two-letter code stamped on a tube's glass envelope or base identifies where it was made, which is a key factor in assessing its quality, rarity, and value to collectors.
Browse TubeDealer listings and filter by brand to find tubes made by General Electric (GE). Many collectors and audio engineers specifically seek tubes with the 188 code for their known factory quality.