CBS 5U4 5U4GB Vacuum Tube Rectifier Black Plates Tray XYZ Crosslisted I am playing them in

I am playing them in one of my Radio Craftsmen RC-2 monoblocks with Super Furry Animals' "Radiator" and they sound great

They come in nifty Western Electric boxes dated April 21

new in box US-made 12F8 tubes tested to spec on our Paul Hart-calibrated TV7/U

and if it is

CBS 5U4 5U4GB Vacuum Tube Rectifier Black Plates Tray XYZ Crosslisted I am playing them inThis CBS 5U4G rectifier tube tested 56 52 where minimum (65%) is 40 40 and 100% is 62 20. It has a crenelated, rectangular top mica spacer and a smooth, rectangular bottom mica; ribbed, black plates, 5943 date codes; excellent flashing and a top, double D getter. It is missing its CENTERING PIN and has been marked for safe and easy insertion. WE HAVE SCORES OF THOUSANDS OF VACUUM TUBES. IF IT'S NOT LISTED, WE MAY HAVE IT. PLEASE ALSO SEE OUT ETSY