Leak Stopper Gloss Black Rubber Roof Patch 3.6 qt (Pack of 4)A revolutionary advancement in roof patching and repair. This long lasting rubberized repair is specially formulated to penetrate deep into damaged areas and stop roof leaks instantly. The secret is Penetrex, a unique penetrating oil that reaches deep into the crack and forms a complete seal. With the addition of liquid rubber, this flexible, high performance plastic cement provides a superior watertight bond that will stop problem leaks for good.