The N1034S is an O-type Backward Wave Oscillator where the magnetic force is provided by an internal solenoid. The N1034A has a permanent magnet built-in in place of the solenoid. It has a frequency range of 2.4 to 4.5 GHz and is also marked as a CV6023.
These images have been taken from an ebay listing.
Top view: the output N connector has a screw-on dust cap fitted.
The B7D base and the two pin solenoid connector. The latter has a red dust cap fitted.
The top of the case giving the Type designations, both commercial and CV plus the solenoid current of 4.2 Amps.
The wide metal tube envelope is 150 mm in diameter, and excluding the base pins is 260 mm tall.
Reference: Data-sheet. Type N1034S was first introduced in 1955.