I didn't know there was such a thing.....unitl I saw it on page 16 of my new S&W book.........under the tree this morning! As circumstances would have it, I just saw one a couple of days ago and didn't have a clue what it was. I believe the one I noticed in the case was a .22 caliber. I'll go back and check if anyone is interested. I think the price tag was ~$1K. Maybe they'll let me take a phot and I can post it.