For scale-free, furnace heat treating of tool steel without an atmosphere-controlled furnace. Saves hours of clean-up. Make parts without losing tolerances due to scale. To use: Clean part, wrap sharp corners with a layer of brown wrapping paper to protect the foil. Wrap part with foil, fold edges double and seal with wallpaper steam roller. Heat treat as usual. Open foil, remove part and air cool or quench. Wear gloves; edges are very sharp! Mfg: Brownells SPECS: .002" (.051mm) thick. Piece- 24" (61cm) x 24" (61cm). Made of 321 SS.