The EL-C1K or C1K as EL is the company prefix is a xenon filled thyratron. The company describes the C1K as a grid control rectifier with an arc voltage drop of typically 8 Volts.
The locating pip for the bayonet base.
The top disc may be the anode. There is a hole in the main cylinder facing the top disc.
The wide glass tube envelope is 39 mm in diameter and, excluding the UX4 base pins, is 86 mm tall.
Reference: Data-sheet. Type EL-C1K was first introduced in 1953. See also1953 adverts.
