I think I know what it is. It came in a tin which has disintegrated if I remember correctly.

I came across it while going through some old collection of bits.

I think it’s from around the late 1930’s.

I very much doubt that there are many other samples of this around now.

Both sides are almost identical with the exception that the trade mark number is only on one side.

It’s about 3 1/2 in dia. And a 1/4 in. Thick. The trademark is 21(9 ?) 047. The number in the brackets could be 9, 8, 6, 5, 3 or 0.

Tried to find info on line but no luck.

Allan C.