3M™ RPF-C (Reinforced Polyurethane Foam) is a polyurethane foam with layers of continuous strand fiberglass and woven roving throughout the polyurethane. The composites are 30% to 45% lighter than plywood, have a high strength-to-weight ratio, very low water absorption (1.0% or less) and will not have any water rot or insect infestation.Information provided by 3M |