Sylvania 5BC3 Vacuum Tube NOS NIB Wristwatch Enhanced Cooling: yes

Enhanced Cooling: yes

engraved base number 78 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

These two GM-Delco 6U7 tubes were tested on our Paul Hart-calibrated TV7/U for shorts

It measured 36/39 where minimum (65%) is 18/18 and 100% is 28/28

Sylvania 5BC3 Vacuum Tube NOS NIB Wristwatch Enhanced Cooling: yesThis new old stock, new in box Sylvania 5BC3 tested to spec on our Paul Hart calibrated TV7 U. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE ALSO SEE OUT ETSY SISTER SITE "LOWTECHTWOO" AND OR CALL OR TEXT US AT 202 372 6931 IF YOU DO NOT SEE WHAT YOU NEED OR HAVE ANY QUESTIONS. 1. MOST FORMS OF SHIPPING EXCEPT MEDIA MAIL ARE AUTOMATICALLY INSURED UP TO $100. ETSY PURCHASE PROTECTION COVERS ITEMS UP TO $250 IN