The UView Combustion Leak Tester, No. 560000, is designed to test for combustion gas leaks from head gaskets, cylinder heads and engine blocks. The tester features a dual-chamber design for higher accuracy to eliminate false readings. The first chamber will filter out any alkaline particles that could result in a false indication of a combustion leak. Test results in the second chamber will provide a true indication of a combustion leak. This tool works on gasoline and diesel engines. The kit includes a dual-chamber tester, tester fluid (16 oz/480 ml) and operating instructions. A positive proof indicates a leak is present when the test fluid changes color. For a gasoline engine, the tester fluid changes from blue to yellow; for a diesel engine, the tester fluid changes from blue to green.