The case of subminiature tube or, utmost MT tube, lead wire can sustain for breadboard experiment. But the case of ST or GT, or Acorn tube, they are heavy or projecting on the bottom and we need some support for experiment. So this time I made 3D printable tube support.

Electrode of ST or GT can be accessed from the bottom. This kind of stable support is quite important especially for the high voltage case (like more than 200V)

These designs are uploaded my Acorn base, or ST base.