• Fire rated expanding foam • 25% higher yield • Fire resistance: up to 4 hours • Reaction to fire: class E • Excellent thermal & acoustic values High yield fire rated, one component gun grade polyurethane expanding foam. 25% higher yield than standard Soudafoam FR fire resisting foam. The rapid curing foam filler provides excellent thermal and acoustic insulation properties. Expands 35-40 times its initial volume. Very good adhesion on most construction materials. Suitable for use in passive fire protection systems as a large gap filler, as well as the installation of fire retardant window and door frames.