Handwritten in green ink around the glass envelope.
overall: 4 1/4 in x 1 7/8 in x 1 7/8 in
This is a tube in a glass envelope with an octal base; pin 6 is missing by design. The tube type cannot be determined because it is nowhere on the envelope or the base. There are several handwritten alphanumerics on the glass envelope that are illegible.