The CV1759 (commercially the 2C26) is a transmitting triode.
The data-sheet describes the 2C26A as a UHF triode pulse oscillator for use at up to 300 MHz.
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 2C26 Type designation on the reverse.
The rounded ends of the cathode tube with four hairpin heater loops within. The control grid copper supports are topped with a radiating fin that then couples to the grid top cap.
The lower mica showing the cathode connection.
The wide glass tube envelope is 29 mm in diameter, and excluding the IO base pins is 77 mm tall.
