The CV349 is an enclosed triggered spark gap or Trigatron. The prototype was the CV6008.
The Trigatron produces 1 μS pulses and these can be repeated 1,200 times a second.
The KB/F identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the F identifies the maker as STC, Paignton.
The resin impregnated basket covering the glass is to retain the fragments if the envelope shatters.
The main electrodes are domed with the gap between. The trigger electrode is not visible.
The upper electrode connects to the top cap.
Scratched into the base is 113 and NR. The three pins can be seen in this image.
The wide glass tube envelope is 70 mm in diameter, and including the base pins is 148 mm tall.
