Air Ministry Amperes Test Guage

Comes complete with a broad arrow marked issue case. The instrument is made by Compton Parkinson Ltd. with patent nos. indicating 1924 and 1927. The dial is graduated from 05-25 and is AM and King's Crown marked. We believe the instrument was used to measure the flow of current through a cable. It appears in excellent condition but on offer as a collector's item only! Measures 8.5" (22 cm)