14 Gauge Galvanized Steel 12" high curb and 3-5/8" wide flange for securing to roof deck Cover includes a 14 gauge aluminum exterio 22 gauge aluminum liner with a TPE draft seal gasket door seal Insulation 1" fiberboard insulation surrounding the base Weathertight Galvanized Roof Hatch with 12" High Curb and 3-5/8" Wide Flange for Securing to Roof Deck, Plus OSHA- approved Safety Railing Welded to Roof Hatch Frame., Lot of 1