This is an adapter to mount some vintage Vacuum Tubes I had in a commonly found RGB wooden RGB mounts.
The RGB block is available on Amazon for under 5 Euros and includes remote.

You may need modify to suit the Vacuum Tube you have - mine had 10 pins. I have included two - one with a curved top and one with flat top. I printed both successfully without supports - but the rounded top would better print with auto supports enabled.

It doesn't get hot - so PLA is fine.