This is a well matched pair of Sylvania 6SN7GTB vacuum tubes. Both tubes test very close to each other. One tube has the Philco factory label, but both were made by Sylvania. Both have a medium glass envelope and a slim, black base. They both have black plates, chrome dome top getters, and faded or yellow or red lettering. These are highly sought after Sylvania 6SN7GTB tubes, act quickly before they 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:

2,375/2,850
2,800/2,425