The CV882 (commercially the 7B6) is a double diode triode, the design use was as detector, AGC rectifier and first audio voltage amplifier in broadcast superhet receivers and effectively was the 6Q7GT on the then new B8B or Loctal base.
The KB/FB identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the FB identifies the maker as STC, Footscray.
The 7B6 Type designation also appears on the glass. The octagonal enclosure suggests an American origin for the basic valve.
The Triode at the top and the screening box for the two diode rod anodes is below.
Here the control grid winding can be seen.
The wide glass tube envelope is 29 mm in diameter, and excluding the B8B base pins is 57 mm tall.
