Wanted: Tube shield that looks like this.
2" Diameter and about 4 - 7/8" Tall. The vent cap comes off.
There are six vent holes near the bottom of the sleeve.
It is the usual plated tin can material... It may or may not be painted. I don't care.
I've learned that the early GM Radio chassis like in the Little General are made like this.. Got a junker chassis to sell ?