The CV3995 is a sharp cut-off amplifier valve designed to operate at 20 MHz and above in IF amplifier circuits. VHF television is one application.
The commercial equivalent is the 6CB6.
The internal construction shows the two inner grids close to the flat cathode and with their wires straight and parallel to the anode. The anode is some distance away and is formed from two plates, one each side of the cathode. The beam plates are small formed sheets with rectangular holes in them.
One of the small anode plates with the rectangular cut-out in the bright beam plate behind.
The envelope is 18 mm in diameter and, excluding the B7G base pins, is 47 mm tall.