Default window shadow dimensions for Snow Leopard?

Question

I would like to emulate the default shadow applied to NSWindows with a CALayer shadow. I can't quite figure out the exact values for the the following properties though:

theLayer.shadowOffset = ?;
theLayer.shadowRadius = ?;
theLayer.shadowOpacity = ?;

I assume that the shadowColor is black (the default).

Does anyone have an idea what those values could be to get a native (Snow) Leopard window shadow?