American Aldes RCR Round Spun-Aluminum Roof Caps are ideal vent duct terminations for sloped or flat-roof penetrations. The seamless, integral roof flashing and weather cap are impervious to water intrusion, and they eliminate the need for curbs on most flat-roof applications. Optional 12″ extensions are available for high snow-load areas. The “0” temper all-aluminum type “1100” construction is highly durable and corrosion resistant. An integral 3-1/2″ collar allows for simple duct attachment. The cap also includes an integral bird screen that can be removed for duct inspection and cleaning. Round Roof Caps are available in sizes 4″, 6″, 8″, 10″ and 12″.