GWI were valve repairers in the 1920s and the advert shows that they were London based. This repaired R Type has simple split-pin base pins suggesting an early example. As the bright filaments had a limited life and valves were expensive it made economic sense to repair them.
The envelope here carries no original maker's identification and it probable that this is a new bulb. The etched lettering is for GWI.
Here the grid can be seen to be off centre and the twisted supports look bent out of shape.
The balloon envelope is 54 mm in diameter and, excluding the B4 base pins, is 93 mm tall.
References: 1005 & 1003. Type R Type was first introduced in 1916. See also1916 adverts.
