Shunic Metal Signals

A friend gave me these recently. Six boxes of "Shunic" Metal Signals.

You'd be forgiven for thinking that they had something to do with model railways. They are actually "signals" for clipping onto pieces of paper in your inbox to colour code them (as illustrated in the image).

A quick check via Google doesn't list a lot about the manufacturer or the product but there is this reference to Shunic: Of 70 Upper Richmond Road, East Putney, London ... Works: North London and Aylesbury. * 1947 Listed Exhibitor - British Industries Fair. Manufacturers of Office Systems Accessories, Signals, Guide and Index Tabs, Visible System Supplies, Suspension Filing Components, ...

I really like things like this!