5Z4G, BRIMAR, ENVELOPE DATE CODE FOR OCTOBER 1959, BLACK BASE
5Z4G, BRIMAR, GREY PRINT OCTAGON CARTOUCHE, BLACK BASE
This valve shows excellent bright getter and has the getter ring situated down by the pinch.
However, more importantly it tests as EXCELLENT using my Avo VCM163 valve tester. This exquisite device has a black low loss micanol base which is tight to the envelope and the pins are clean, straight and uncorroded.
Device specification 60mA delivery for both diode sections. So you can see we have 100% emission from this venerable beauty.