This exhibit has lost the Type identifier. We have the filament rating and the fact that it was made in Austria. The base style matches Triotron buy we can not find a visual and specification match for this small signal triode.
The pinch and base with simple split pins.
In this image the shape of the anode and control grid can be seen. The filament is a single vertical strand.
The anode is a bright cylinder with a single support running up the side. The grid helix is fixes to a support on one side only.
The wide glass tube envelope is 25 mm in diameter, and excluding the B4 base pins is 85 mm tall.