Great Stuff Pro™ Gasket is a one-component, water-based foam applied to the top plate, bottom plate and around the perimeter of all rough openings. Specially designed to create a flexible, compressible, air seal that will stay in place when drywall is installed. Top plate to attic drywall air sealing is consistently ranked as the #1 air sealing location. Great Stuff Pro™ Gasket forms a seal between framing lumber and drywall, which can result in up to 1.6 ACH50 reductions.