1930's RPM Gauge Help.

Morning Folks,

A friend found this vintage gauge at a boot sale where it was sold as ‘salvaged from a boat’. Lucky for me, knowing of my interest in vintage aircraft, he acquired it for me.

It’s marked on the front dial face as Mark 5 Type 1 – Non Luminous – Hirst Bros & Co Ltd. Oldham. It’s also marked with No 201/C.H.

The rear is marked with an ‘A’ above a military arrow which suggests military aircraft use.

It reads up to 2600 RPM which doesn’t seem high enough for a fighter type. Does anyone have any info on what these were possibly used in or likely period of manufacture?

[ATTACH=CONFIG]246923[/ATTACH]

[ATTACH=CONFIG]246924[/ATTACH]

Thanks

John