that was released at SIHH 2009.
The previous 1815 in Platinum had no L/E to it, but this new one is released in an L/E of 500 pieces.
For your info the case diameter is 40mm, and the movement is a new one entirely made by Lange ( as opposed to the older one which had Jaeger parts in it, and was 35.9mm )
Cheers
Stephen