Another advantage of grade 304 stainless steel bar over grade 303 is that it is slightly harder and has better corrosion resistance. Because of this, grade 304 stainless steel bar is used in large quantities in the manufacture of fasteners and fixtures such as nuts, bolts, washers, clips, fittings and clamps. Products made from grade 304 stainless steel in the fastener industry are often referred to as “A2”.