Bucking bars, rivet sets and rivet gun. The two larger bucking bars were found at Harbor Freight for about $8 each. The smaller bar is a very expensive tungsten bucking bar. The tungsten bar probably weighs more than twice as much as either of the other bucking bars. The rivet sets fit into the rivet gun and are held in place by the large coil springs. The flush set swivels and has a rubber collar to help hold it down in place on the material. The other sets are a straight set, back-rivet set (spring loaded), and offset rivet set. The rivet gun is a 3X. There is a small air pressure adjustment knob on the inlet.