It looks like the version from SOG, which had a habit of chewing up some rails I've used them on. I played around with one for awhile, and then gave it away. The one I used kept coming loose.
The person I gave it to likes it, and used several layers of electrical tape to stop it from chewing up his rail.
Not a lot of info, but my time with it was fairly short. It is not an uncomfortable grip, but it may feel better to people with smaller hands. The new owner of my old one falls into that catagory.