Pair of RCA Cunningham type 27 vacuum tube tested at new old stock
Tested with a calibrated TV-7D/U tube tester.
Calibration by Daniel Nelson.
Tested at: 42
Average new: 42
Minimum good: 25 
The minimum is equal to 65% of the life of the tube.
Tested for shorts and gas.
Date code: -
NOS/Used: used
Construction: black plate foil getters
Glass: clear no burn marks
Base: tight
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!