The 10F1 is an early all glass screened amplifier pentode. The high impedance suggests applications with tuned circuits as anode loads, such as RF, or more likely due to the high gain, IF amplification in superhet radio, television or radar receivers.
The pins are located equi-spaced around the base circle and the metal skirt and spigot aid location. The pins are short and hard as was the case with early all glass designs.
Andy Talbot remembers dismantling a TV receiver from the late 1940s or early 1950s (Band I only) that used lots of 10F1s.
The control grid is wound on copper supports and a radiating fin is attached at the top. The wide helix of the suppressor grid can be seen through the holes in the carbonised cylindrical anode.
A view of the top mica. The cathode tube is rectangular.
The wire grids g2 & g3 can just be seen through the anode.
The thin glass tube envelope is 19 mm in diameter and, excluding the B8A base pins, is 51 mm tall.
References: 3002 & 1040. Type 10F1 was first introduced in 1948.