The 6F19 is described as a VHF varible-mu pentode, this places the valve in a superhet context with AGC applied to the RF and IF sections. It was a television valve and the frame grid valves overtook its performance.
The anode is formed from two small curved plates joined by a single strap. There are screens above and below the micas that connect to the mesh screen.
The envelope seems larger than required by the electrode assembly.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 57 mm tall.
References: Datasheet & 1040. Type 6F19 was first introduced in 1959.