The CV1129 is an RF pentode based on the MS/Pen/T. Older service names were the NR71 and the VR129.
The KB/K identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the K identifies the maker as ETEL, Electronic Tubes, High Wycombe.
The gettering hides the internal structure. The grey plastic sleeve is shrunk to hold the base cap firmly in place thus augmenting the cement.
The top mica and screen encloses all electrodes.
The classic envelope is 44 mm in diameter, and excluding the B7 base pins is 107 mm tall.
