Domed Head POP® Rivets. Aluminium POP® Rivets. Standard open type domed head rivet, for general purpose use Aluminium alloy (3·5% magnesium) body, carbon steel mandrel. Steel POP® Rivets. Standard open type domed head steel rivet Increased strength and temperature resistance Carbon steel body and mandrel. Premium Quality Steel POP® Rivets. Mandrel head retention Excellent hole fill capabilities Large blind side bearing area High shear and tensile values to standard steel products Carbon steel body and mandrel. Stainless Steel POP® Rivets. Standard open type domed head stainles steel rivet Increased strength and temperature resistance Good corrosion resistance Stainless steel body and mandrel