This is a matched pair of Sylvania JAN 6X4 vacuum tubes. These tubes have a 7 pin tall glass bottle with Sylvania markings on the tube. They were made in the legendary Philco Lansdale factory shortly after Sylvania purchased the factory. They tests very strong, with greater than NOS readings. These tubes have black plates, clear glass, yellow lettering, and square top getters. This is an excellent Sylvania 6X4 tube that is highly sought after, act quickly before these sell out! More available upon request.
Be careful buying tubes from sellers who list tubes as matched if they do not provide test results or the equipment that they tested their tubes on.
I personally tested these tubes on my recently calibrated Hickok 600a and my TV7D/U and the results are as follows:
Pass/Pass
*Rectifiers test on a pass fail scale, they are not measured on gm or transconductance.
| Listed | a year ago |
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| Condition | Excellent (Used) Excellent items are almost entirely free from blemishes and other visual defects and have been played or used with the utmost care.Learn more |
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Product safety information may be available here.

