Henry 900 Flashing and Construction Sealant – Gray is a single component, moisture-curing compound formulated for use as a general purpose construction sealant. When fully cured, Henry 900 Flashing and Construction Sealant – Gray forms a tough, durable bond. Henry 900 Flashing and Construction Sealant – Gray aggressively adheres to most common building materials and is paintable when fully cured.