6" Malleable Aluminum Chimney pipe Flashing6" Secure Temp Roof Flashing, 1/12-7/12 Pitch Malleable For Metal/contoured Roofs, AluminumThis flashing has a hole in it that is about 8 1/2" in diameter that can be cut open a little larger for a larger pipe diameter but caution needs to be taken not to cut it too close to the roofline to allow leaking from splashing water. A storm collar is placed over this and all flashings to make a seal to the chimney pipe which is then sealed with silicon caulking for a waterproof installation.