Mullard 61SV Vacuum Tube Photo Tube NOS NIB 6550 They all test on or

They all test on or near the cusp

This is a late-40s pressing with some scratches and moderate surface noise

These nine TCA UY-224 globe

This Sylvania 6B4G tubes was tested on our Hickok Paul Hart-calibrated TV7/U for transconductance

MOST OF THE ITEMS WE SELL ARE OVER 70 YEARS OLD

Mullard 61SV Vacuum Tube Photo Tube NOS NIB 6550 They all test on orThis new old stock, new in box Mullard 61SV IR sensitive lead Sulphide photoconductive cell tested to spec on our Paul Hart calibrated TV7 U. It has 93S6 provenance date codes. 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