Cover:14 gage galvanized steel / .125 aluminum in box type design with 1" rigid fiberglass insulation and 22 gage galvanized steel / .040 aluminum cover liner. Continuous santoprene weather / draft seal is attached to inside of cover to provide a flush, tight fit.
Curb: 14 gage galvanized steel / .125 aluminum with 1" rigid fiberglass insulation at curb exterior. Curb is 12" high, and has 3-1/2" wide mounting flange with pre-drilled holes.
Hinge: Steel butt hinges with brass pin.
Opening Device: Fully enclosed compression spring operators allow cover to open against 10-lbs./sq. ft. wind or snow load when released.
Latch: Manual inside / outside release that works with a fusible link or a resettable electric link (optional).