VT4-B Westinghouse

Dear friends I have three VT4B Westinghouse tubes but two of those have yellow spot (something like paint) on top.Please tell me if you know what this mean and his value.Thank you and best regards
That's a military designation for the 211 tube,  more commonly seen as VT4A or C .    Value would depend on overall condition and test measurements.
Thank you very much for your reply but i still do not know what it means yellow paint on top
No clue here either. I’ve never seen one with a yellow top.   Perhaps these guys can answer that: (https://www.vacuumtubesinc.com/2016bid.pdf)