ASMACO Window & Door PU Foam is a single component, moisture curing polyurethane foam that is designed to form a water resistant, airtight seal between rough openings and frames. Ready-to-use and easy to apply. This foam is designed to minimally expand, insulate, and seal around windows & doors without bowing the frames. A cost-effective and simple solution to unwanted airflow in your construction projects. Suitable for filling cavities and through penetrations. Can be applied with a straw or a foam gun.