Strong WD-12
DC Det/Amp Triode
~1923

This tube was apparently a bootleg WD-12, sold by Harry Strong, located on 34th St in New York City. It is not known if Strong was the manufacturer or just a dealer. According to documentation supplied with the tube, it was purchased by an RCA agent on Oct. 11, 1923 as a part of their investigations into unlicensed tube manufacturers.