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You are buying 2 tubes, a factory matching pair of mint NOS NIB NEW USA milspec Philips 6X4WA / 6X4W, date code will be either December 1986 or October 1986, blue label, black plates. 6X4WA/6X4W is premium military-grade version of 6X4, highest quality manufacture.
- Each plate section tested strong emission
- each plate section has been oscilloscope tested, in a real circuit, to verify good balance between plate sections
- No shorts or leakage
Emission/shorts/leakage was tested on my professionally calibrated Western Electric KS-15560 (advanced version Hickok 539B) tube tester.
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