Willseal® Seismic is a pre-compressed, self-expanding open micro-cell polyurethane foam impregnated with a hydrophobic, acrylic polymer and coated with a factory-applied silicone sealant. It is designed to provide a watertight, dust-proof, noise-reducing, thermally insulating, and UV stable primary seal that does not require invasive anchoring for installation. Willseal Seismic is capable of +/- 50% movement from the mean joint size.