The EF89 is a miniature RF variable μ voltage amplifier pentode for use as an RF or IF amplifier in FM/AM receivers and is designed to work with a tuned anode circuit.
Through the hole in the screening mesh can be seen the three wire grids. The anode is a pair of plates one on either side of the central cathode.
The back of one anode plate. The grid wires extend beyond the width of the anode.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 52 mm tall.
References: Data-sheet & 1040. Type EF89 was first introduced in 1954. See also1954 adverts.