I won this lovely silver thing on eBay a few days ago, for all of £4.00 including postage:

Clearly it’s a buckle; I think it would have gone on the belt of a 1930s dress – one of those fitted dresses with a demure collar, a nipped-in waist and a flared skirt. There’s some damage to the enamel but it still looks good. I’m thinking I might thread it onto a piece of velvet ribbon and turn it into a bracelet.

Here is the back:

It’s stamped with a serial number (735426), a faint “925” and the word “Silver”.