We're just getting all of the parts in for the new "Fang" for our Grapples and have been putting them on some of the units going out. Their main purpose is for keeping round objects (aka firewood logs) from spinning while sawing or cutting. But they are also good for breaking things up and additional holding in various other ways. They simply bolt on so they can be added and removed easily in minutes.
They'll be added to the website asap, but here's a quick photo.