This was purchased at a Poundland store in the UK, the brand is Jane Asher. Orignally for producing 6 pop cakes. It has two silicone halves which press together.
If you press the mould sections inwards they will stay in place, here we have illustrated the letter 'B'.
The two halves can also be used separately and will take small balls in the recesses to help with Braille letter recognition, and if you buy a few together, even short words.
Editor's Note: These are available through various sources in the United States as well, if you search for "Sillicone Pop cakes mold". Click here to see an example.