The EM85 magic eye or tuning indicator is a fan shaped green display device. The changing grid voltage alters the width, or angle, of the fan.
Thanks to David Horton for these images.
The display screen seen face on.
The target seen in semi-profile showing that the screen is a two dimensional curve.
The screen in profile.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 65 mm tall.
Reference: Datasheet. Type EM85 was first introduced in 1955.