In case of a damaged gasket under the cylinder head or the cylinder head itself, a part of the exhaust gas, among other things contains the CO2, which enters the cooling system. The operating principle of the device is based on measuring the CO2 content. With an increased content of CO2, the liquid reacts with the gas and changes colour. The whole process takes only 5 minutes. Our tester offers almost 100% safety if the cylinder gasket isnt broken.