I'd prefer to post an intact one here but this is the best I could come up with today. I found it in a recently ploughed field alongside an abandoned railway and not far at all from where I found the dark cornflower blue 742 last May 2013.

This M.T.Co embossed (what's left of a threadless insulator) is also blue but I'm not sure which shade since I haven't bothered cleaning it yet.