Tested with a calibrated TV-7D/U tube tester.
Calibration by Daniel Nelson.
Date code: matching 337
NOS/Used: new?
Construction: black plate
Glass: clear with chrome top
Base: tight
Tested at: 50/48 52/52
Average new 55/55
Minimum good 40/40
The minimum is equal to 65% of the life of the tube
Tested for shorts and gas.
30-day free return. Your items will be packed very well and shipped promptly.
We combine shipping on tubes.
Always glad to answer any questions.
Thanks for looking!