This unique imported Foam allows for some unique building designs. It has a distinct grain that allows a tight roll in one direction and a stiff foam 90 degrees from that. It is perfect for skinning airfoils, fuselages and ducted fan designs. The panels each have a smooth side and a ribbed side. These ribs allow bending without cracking or fracture. The ribs run parallel to the shorter edges (23" edges). This pack contains 5 sheets each measuring 23" x 31".