The LD210 is a battery amplifier triode designed for detector of audio voltage amplifier use.
The bright anode with the filament tension spring support in the foreground.
The dome carries the identification and the five pointed star is characteristic of Tungsram. This exhibit was made in England and not imported. The single strand filament can be clearly seen.
Looking directly down on the dome shows the relative spacing of the electrodes.
The classic envelope is 39 mm in diameter and, excluding the B4 base pins, is 83 mm tall.
References: 4063, 4064, 1040 & 1043. Type LD210 was first introduced in 1935. See also1935 adverts.
