The HL210 is without markings on the envelope or base. The pinch has HL210 written on it. The HL210 was made by Mazda and MOV.

An unusual Bakelite base and unusual spiral split pins.

The close-up shows two sets of support rods. The inner pair hold the filament ends. The base of the single V is held below the anode box.

The balloon envelope is 42 mm in diameter and, excluding the B4 base pins, is 94 mm tall.

 
Pin Connections

B4	1	2	3	4
	a	g1	f	f

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	ra	gm
	2.0	0.1	150	28k	0.5

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 19 April 2008 {find valves by name}