Polyprene® is an all rubber, universal roof repair cement used for flashings, seams, pitch pans, cracks, splits and making various repairs on all roof types. It provides you with a long-lasting, water-tight, 100% rubber seal. Polyprene® was voted the #1 repair compound among roofing professionals. The heavily fibered high-solids content prevents mud cracking, making it ideal for pitch pans as well as to seal seams, cracks, around vibrating rooftop equipment, skylights, vents, flashings, and more. In emergency situations, wet surface adhesive agents allow repairs even to damp metal.

One pail contains 20 Liters and it is enough to do 5-cm-width flashing for more then 120 meters long!!! (2 in. width and 400 feet long flashing)

Click on the following link to see Polyprene in action
https://www.youtube.com/watch?v=fBT3jGa4VNo