The RJW was made by Seddig RIW in Wurzburg Germany. The special four pin base has a shorter pin for the anode. The general arrangement of connections is the same as the B4 base.
The pinch is elaborate with four glass rods holding the supports.
The horizontal anode has a geometry close to that of the TM.
The base pins: all are hollow but three have splits that enable them to have a slight barrel shape to grip the socket.
The anode and support wires look to be made of copper. Copper has a melting point well below the operating temperature of the filament and so it may be plated nickel.
The geometry of the concentric electrodes.
The lettering is etched into the glass. The Serial Number is 21826 and is written on by hand. The image shows that the filament strand is still intact.
This image shows the construction very well. The anode folds over the central glass extension to the pinch stem and wire is passed through holes in the anode and passes via a notch in the glass to the other side where it is twisted together.
The etched and printed lettering.
The lettering from a different angle. The actual lettering is too faint to be seen clearly without a little enhancement.
The wide glass tube envelope is 42 mm in diameter, and excluding the base pins is 101 mm tall.
Reference: 3002. Type RJW was first introduced in 1917.