The UY85 half wave rectifier was designed for use across the European mains, as the 100 mA heater suggests. The reservoir capacitor specified is 100 µF and the minimum effective series resistance in the circuit needed to be only 100 Ohms.
The probable use was in domestic broadcast receivers for the main HT rail.
The anode end on. Here the bright inner surfaces of the Nickel sheet are on view. Bending the anode plate like this increases the effective radiating surface area.
A close-up of the base and lower portion of the anode. The red platinum portion of the composite pin is clearly visible inside the pressed glass foot. The latter is formed from a short length of hard glass tube that when soft at great heat has been moulded to form the base.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 58 mm tall.
References: Data-sheet & 1040. Type UY85 was first introduced in 1954.