Leak finder for pipe lines, tanks, coils, cylinders and valves;Air leak detector also designed to protect pipes from corrosion;Creates large, long-lasting blue bubbles that remain on surface to allow extra time for leak detection;Detects even the smallest and slowest gas leaks;Contains propylene glycol and will not freeze;High-viscosity formula clings, even to vertical surfaces;Will not harm or stain metal, rubber or plastic surfaces;Non-toxic;FBC-approved formula