This 7-3/4"W x 5-3/4H x 5-12"D unit is 1/4" undersize from nominal size for ease of installation. Made with 16 gauge galvanized steel and heavy-duty molded nylon bearings for long lasting durability and dependability. Plated steel angle linkage and parallel blade. Supplied with blade and jamb seals for minimum damper leakage. Locking quadrant manual actuator. May be used in conditions up to 200°F.