The Avominor was a smaller version of the popular Avometer universal multimeter that had been introduced back in 1923. We have looked at an Admiralty pattern Avometer here, and today’s example of the smaller Avominor is one purchased for use by the RAF. This instrument is about have the size of the Avometer and a lot lighter and more portable. This pattern was in use from at least as early as 1935 and had a black Bakelite case with a central dial and a variety of different points wires could be plugged into:

The rear of the Avominor has a printed tinplate sheet with instructions guiding the user how to work the instrument:

This plate is hinged and allows access to the interior to change the battery. These instruments used an Ever Ready U10 battery, a now obsolete 4.5V battery. The Avominor comes in a leather carry case, with a strap allowing it to be slung over the shoulder:

This case has a very nice Air Ministry stamp on the leather and has the usual RAF style of stores code:

A full set of instructions from the period showing how to use the Avominor can be found here.