The CV35 is a tunable reflex klystron that has an International Octal base and was designed to operate as an oscillator at a wavelength of 10 cm (3 GHz) and replaced the NR89.
A range of Types existed to this design, varying only in frequency. These were the CV35, CV36 and CV69. These all operated with voltages above 1 kV and were a problem for airbourne use. The replacement design was the CV116, CV238 and CV272.
The mounting plate can be seen in the picture. As is typical of reflex klystrons the reflector is taken to the top cap. The inset picture shows the external cavity.
The thin glass tube envelope is 31 mm in diameter and, excluding the IO base pins, is 165 mm tall.
Reference: Datasheet. Type CV35 was first introduced in 1941.