Up for sale is a pair (2 Pcs) of high-grade vintage NOS GE JAN-5687WB medium-mu dual triode audio tubes, packed in original government boxes. Manufactured in the USA to rugged joint Army-Navy (JAN) military specifications, these premium tubes feature heavy-duty black plate construction, a top ring getter, and durable glass envelopes. Famous in high-end audio preamplifiers, driver stages, and headphone amplifiers for their outstanding current drive capability, exceptional dynamic impact, and linear transparent reproduction.

Both tubes have been tested on an Amplitrex AT1000 automated valve tester at nominal reference settings. Plate Current (Ip) and Transconductance (uMhos) measurements alongside percentage performance ratings relative to standard factory specs are detailed in the table below.