constructed of a 24 gauge galvanized steel double panel door and frame with mill finish for long lasting durability. 1/8″ thick x 1/2″w closed cell neoprene gasketing between insulated door and frame assures tight seal without obstruction in air system. Frame includes 5/8″ notched knock over tabs. Door panel filled with 2″ fiberglass insulation compressed into 1″ and includes aluminum continuous piano hinge. 24″ w x 24″ h outside flange dimensions. 22-3/4″ w x 22-3/4″ d x 5/8″ h return flange dimensions. Color finish is silver . Number of latches is 2 .