Catalytic converter is an important tools to prevent about a pollution problem, wherever this problem every time growth up, why the pollution problem every day growth time ? because many people using a engine, whoever this engine work with gasoline, and gasoline having many partikulat, and this pertikulat will be reaction with air in the engine an production many more poison gas like HC, CO and CO2. In the air, gas like HC make people can’t breath normally because this gas make your bronchi become smaller and people difficult to breath, CO gas make cancer skin, CO2 gas make pollution in the air. All about it this tools (catalytic converter) is important, ths tools work with chemical reaction, in the chemical reaction the poison gas breaking to become normally gas in the air, the chemical reaction is oxdidation this reaction cracking gas HC, CO, CO2 to become H2O and O2. But this tools have stiff price so in here the writers try to produce a tools works with catalytic converter but with lower price