W.D. Circuit tester

[Bob7.62W]

It's a circuit tester, made by GEC in 1945 and it's military, but does anybody know who would have used it and for what purpose? It appears too fragile to have been used in the field, although it has a hanging loop that suggests that is was intended to be carried about. Box size is three and a half inches by three and three eighths by two and three sixteenths thick. Dial reads; Detector Q & I MK1 (W.B.0274) Serial number20S6 G.E.C. Side of box has a white stamped crown and the number 699.

 

[exat808]

Hi Bob - The Q & I galvanometer or Linesman’s detector, designed to make measurements of both Quantity and Intensity (in effect current and voltage) used two coils of low and high resistance respectively. They were sufficient for making comparisons, but not precise measurements. Another example at http://www.electrokinetica.org/d3/1/2.php

 

[Bob7.62W]

Thanks Danny, I saw one here; https://www.the-saleroom.com/en-gb/...0229/lot-9825a678-d747-43eb-ab47-a6e400bf5bd0 that is similar (different make) but was no wiser as to it's use.
As you say, it's not a precise instrument, it only reads zero when perfectly level, Laying flat with a slight tilt and the reading goes up to 70!