Those are Nill's grips. I just bought an interesting set myself to put on a S&W 686 Competitor. They make a great product. I have the grips, and I pick up the gun on Saturday.
I plan to put a set on my 460 at some point also, but those will be a touch more painful to shoot with.
The thing I couldn't believe was that when I took mine out of the package, at first I thought they were one piece grips, as the wood was so finely cut I could not see the split between the two halves through the checkering. They are that precisely made. The Germans know how to make stuff, that's for sure.