Their ThermoTech 21 engineered panels feature 18 ga. EPS foam is ozone-safe, because it uses air for a blowing agent, rather than CFC and HCFC compounds used by some other foam makers. The panels are made by first routing channels for the 1x2 steel tubes. They are placed on opposite sides of the panel every 24-in. Each tube is connected to its mate with a long screw.
Foam separates the opposing steel tubes, preventing thermal bridging.
Four steel angles placed on the top and bottom edges join the steel tubes. These angles can span the ends of adjacent panels to lock them together. 32 ft. long. Siding screws directly to the tubes. Window and door openings are built into the panels and wrapped with 2x8 lumber.