Increase home comfort and energy efficiency with GREAT STUFF Insulating Foam Sealant Our GREAT STUFF Gaps & Cracks Insulating Foam Sealant attacks air leaks with a vengeance It sprays right into gaps and cracks up to 1” (25mm) in diameter It expands to fill the shape of the gaps It forms a long-lasting, airtight, water-resistant seal It helps keep insects, moisture/condensation and allergens out.