We have had several customers order Critter Quitters for rubber flashing. Critter Quitters will fit rubber flashed vents, but they simply don’t serve the same purpose as lead flashing. Squirrels do tend to gnaw on the pipe sometimes, and Critter Quitters will stop that. Plus it will keep the frogs and rats out, and beautify the roof instead of ugly white pipes sticking out of a black rubber grommet. However, they will not stop a rubber grommet from leaking. So if you want to give them a try feel free.