Kool Lastik, 4.75 Gallon, Heavy Duty Primer, Rubberized Undercoating, Recommended For Troublesome Roofs Including: Modified Bitumen, Rolled Roofing, Bonded Tar & Gravel, Built-Up Roofs & Most Asphaltic Surfaces, Also Recommended For Roof Problems: Ponded Water Areas, Standing Water Areas & Flat Roofs, Use With The Kool Seal Elastomeric Roof Coating System To Repair & Prevent Leaks.