Too often we look at a truck as a whole entity without considering it is a sum of its parts, some of them are intriguing works of art in their own right.
Now, every CMP over 8CWT would have had one of these, let's see who can guess what it's purpose is first.
Hint: It's not what you'd call a fast moving part in the catalogue, nonetheless they had to be supplied as spare parts. It would make an ideal paperweight.