The CV286 is a miniature voltage stabiliser.

The striking Volts are 110 and for burning currents of 2 - 10 mA the regulation is 5 Volts.

We have another example of this valve. Note the dark interior to the glass.

Unusually for a CV valve this one has the GEC logo sticker attached. The sticker says made for GEC.

The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 45 mm tall.

Reference: Datasheet. Type CV0286 was first introduced^¶ in 1954.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	k	k	k	-	a	a	a

 
Absolute Maximum Operating Conditions^¶

Stabiliser	Va	mAa
	95	10

Thanks to Frank Philipse for supplying the above PDF datasheet