A Fast, Economical and Accurate method to test for combustion gas leaks from:
Head gasket leaks
Cylinder head leaks 
Engine block leaks
NEW & IMPROVED! Dual-Chamber for Higher Accuracy Test
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.

Works on Petrol and Diesel engines.
Includes:
Dual-chamber tester
Tester Fluid (16 oz./480 ml)
Operating instructions
Positive Proof that a leak is present when the Tester Fluid changes color!
Petrol Engine: Tester Fluid changes from blue to yellow.
Diesel Engine: Tester Fluid changes from blue to green.