Complete Combustion Leak Test Kit: Includes fluid and all necessary components with nothing more to buy for immediate testing | Easy Visual Indicator: Fluid turns from blue to yellow when combustion leak is present, providing clear and instant results | Comprehensive Leak Detection: Tests in seconds for combustion leaks caused by blown head gasket, cracked head or block, pulled bolts or studs, and warped sealing surfaces | Quality American Manufacturing: Made in USA for over 45 years with limited lifetime warranty ensuring long-lasting reliability | Convenient Storage Solution: Comes in a box suitable for tool storage to keep your kit organized and protected | Versatile Engine Compatibility: Works with virtually any liquid-cooled internal combustion engine including gasoline, diesel, propane, natural gas and alternative fuel engines with closed cooling systems