DIAL 20" X 20" Down Draft Evaporative Cooler Roof Jack About This Product We manufacture our Roof Jack out of sturdy galvanized sheet metal. It provides a secure platform for your roof-mounted evaporative cooler. Use cooler legs to support the cooler's full weight. 19-3/4 in. discharge opening Ideal for all major brands of roof-mounted, ducted, downdraft coolers rated from 5,500 CFM - 7,000 CFM Adjusts from flat to 6/12 pitch Slide-in winter damper included Product Information Internet # 100345700 Model # 78318