The E1985 is an experimental valve from M-OV and this one carries the serial number 71. It is a half wave rectifier, the heater is a vertical insulated coil and the connections are top and bottom. The cathode also is connected at the top. The anode is X shaped with a small round centre cavity for the cathode tube. The heater seems to be for series use as it takes a small current at 30 Volts.
The top of the anode showing the heater and cathode connections.
The top heater connection passing down the envelope to pin seven.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 59 mm tall.