The CD13 is a miniature end-view nixie tube made by the company Rodan-Okaya of Japan. The photographs show two variants. The yellow-label CD13, and the later black-label CD13a. The CD13a is shown with the original packaging and a socket.
The datasheet is after the photographs.
This is an excerpt from a catalog at Dieter’s excellent web site.CD-12 data
Socket type: TSM-11P