... 2002 3.Longlife,good after service Piston ring set for Caterpillar 3304(auto parts) 1.Casting:Single ... line,Chrome plating product line,Equipment for steel belt composite ring(Japan),Pedrail shotting machine,Automatic ... for internal combustion engines.These are the barrel surface ring,keystone surface ring,cone surface ring,twist side ring,chromium plating ring,spray molybdenum ring,nitride ring ...