The 30FL12 is a triode beam tetrode with a high slope (gm) designed for use as a video output stage. For such wideband functions a high μ is essential. The 30FL12 was also issued under the type designation PCE82.
The triode is on the right and both sections can be seen to have copper control grid supports.
The triode with the flat cathode and two part anode stitched together.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 47 mm tall.
Reference: 1040. Type 30FL12 was first introduced in 1961.