The 4C35 is a hydrogen thyratron designed for switching in-line modulator circuits of microwave radar. Other uses include induction heating and pulse modulation.
In essence this type of valve acts as a fast switch with low on resistance and momentarily connects a bank of charged capacitors across a magnetron and thus delivers a pulse of a high power for a few microseconds.
A serial number. The locating pip for the bayonet base can be seen on the right of the metal base skirt.
The shield with perforated top section. The anode disc is within and the anode connection is within a glass tube that the shield is clamped to.
The lower electrodes and locating pip.
The wide glass tube envelope is 63 mm in diameter, and excluding the base pins is 150 mm tall.
References: Datasheet. Type 4C35 was first introduced in 1954.