National 7B4 loctal vacuum tube chrome top new old stock in box.
Tested with my calibrated TV-7D/U tube tester.
Calibration by Daniel Nelson.
Tested at 43 
Minimum 25 
The minimum is equal to 65% of a new tube. 
Tested for shorts and gas. 
30-day free return.  
Your items will be packed very well and shipped promptly.
Always glad to answer any questions.
Thanks for looking!