Great Stuff Pro Gaps & Cracks Insulating Foam Sealant is a minimal-expanding, single component polyurethane foam sealant for general purpose building envelope air sealing. Recognized as a fireblock, Great Stuff Pro Gaps & Cracks resists the free passage of flames to other areas of the building through concealed spaces (USA only). Designed to fill gaps up to 3" (75 mm), Great Stuff Pro Gaps & Cracks Insulating Foam Sealant expands to take the shape of cracks and voids, forming a permanent, airtight and water-resistant bond to vinyl, wood and metal surfaces. Once cured, it remains soft and flexible permitting natural expansion and contraction of surrounding surfaces. Helps prevent drafts and repel water, enhancing energy efficiency and improving occupant comfort. Sandable and paintable. Reusable straw applicator included.