A trio of ICF systems include knock-down and preassembled interlocking blocks to create walls between 4 and 24 inches thick and 60 feet high. The systems offer two- to four-hour fire resistance based on core thickness, a noise rating of STC 50 or higher, and resistance to F5 tornado winds. The ARXX Prime system (shown) is available with a 6-, 8-, or 10-inch core width and features an exposed web design (furring strips) on both faces for attachment of finish claddings. The products include recycled content and emit no VOCs. 800.293.3210. www.arxx.com.