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 complete seal. With the addition of liquid rubber, this flexible, high-performance plastic cement provides superior watertight bond that will stop problem leaks for good. Product formulated to be used year round. Stops roof leaks instantly. APP and SBS compatible.