The RCA 6JU8A is a quad signal diode with a central screen between the two pairs. The 6JU8A is described as a general purpose quadruple diode for use in phase detector and noise immune colour killer circuits of colour television receivers, and/or FM stereo equipment.
The face of one section. The size and rating is virtually identical to the signal diodes in the EB91 double diode.
The two pairs of diodes with the electrostatic screen in the centre.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 49 mm tall.
Reference: Data-sheet. Type 6JU8A was first introduced in 1964.