Quote Originally Posted by Zilch
From the red dots, both are D16R2425.

Bottom one has homebrew Aquaplas coating; factory don't coat the diamond surround, as I recall.

[Not that it's a bad idea, tho, of course.... ]
Congratulations Zilch, you are the winner of the quiz!

I will contact Lord Zilchmeister early next week with details of the mystery prize.

Ian