You can probably guess what this one is for. Setting copper rivets, of course. A "two-in-one" tool, one side sets the burr onto the rivet, and the other end rounds off the stub that protrudes. These are the things I had to get the big maul for! I even got the thick slab of marble for setting these, but after I broke my thin piece of marble, I decided to do my copper rivet setting on the concrete floor of my garage!